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THE CLEANING ^W 

ELECTRO-PLATING 

of M ETALS 

A manual of information 
and instruction written 
for the benefit of the 
Electro-Plater and those 
interested in the art of 
Electro-Plating 

By Herman H. Reama 
Brooklyn, N. Y. 

B 

Printed by the 

Oakley Chemical Company 

for 

Members of the American Electro-Platers Society and 

The Plating Trade 



El 



The Metal Industry Print 

99 John Street, New York 






Ca/y^te^/rep /f/5 iV veRMA/i/ /f. {(a4ia. 



Copyrighted 1917 

Oakley Chemical Company 

New York, N. Y. 



P-- /7^/-^ 



0)C!,fl597639 

OCT -2 1920 



PREFACE. 

This book has been written to offer in a 
non-technical manner, the best methods of cur- 
rent practice, in the electro-plating of metals. 
Enough supplementary text, on the preparing 
of metals for plating and the analysis of solu- 
tions has been added, to make the information 
coherent and complete. 

In compiling this book, I have endeavored 
to make it practical in every detail, wording it 
in concise and simple language and avoiding 
technical terms as much as possible. 

I trust it will prove of benefit to my fellow 
members of the American Electro-Platers' 
Society, and to platers in general. 

HERMAN H. REAMA. 

Brooklyn, N. Y., 1917. 



The Cleaning and Electro-Plating of Metals 1 

THE BASIS OF ELECTRICAL RULES. 

IN order that the operator of an electro-plat- 
ing plant may intelligently handle the cur- 
rents used for the plating baths, and turn 
out work efficiently, it is essential that at least 
the fundamental principles of electricity should 
be understood. 

The cause of a manifestation of any kind of 
energy is force. Electric energy in the form 
of a current is caused by a difference of electric 
potential, or electromotive force (e.m.f.). The 
unit by which this force or pressure, which 
causes an electric current to flow, is measured, 
is called a volt. The current which flows is 
measured in amperes. The unit of resistance 
to the flow of current in a conductor is the ohm. 

One volt is about the value of the potential 
of a Daniell's Cell ; it is the electromotive force 
which will force a current of one ampere thru 
a resistance of one ohm. One ampere is the 
current which will plate out 0.01973 grams of 
copper per minute from a copper sulphate bath. 
This measures not only the current intensity, or 
available working energy, but also the rapidity 
of its work : — a current of 10 amperes can do 
in 1 second, what a current of 1 ampere requires 
10 seconds to do. One ohm is the resistance 
at 0° C. of a column of mercury 1 meter long 
and 1 sq. m.m. in cross section. The coulomb 
is the unit of quantity of electricity and is the 
amount of electricity carried by a current of one 
ampere in one second. 



2 The Cleaning and Electro -Plating of Metals 

Ohm's law expresses the relationship in an 
electric circuit, of the voltage, current and 
resistance, as follows : 

The voltage is always equal to the product 
of the current and the resistance — Volts = 
Amperes X Ohms. If 6 volts are impressed on 
a circuit of 2 ohms resistance, 3 amperes will 
flow. 

This law may be expressed in two other 
forms : 



volts 



Amperes = 



Ohms = 



ohms 
volts 



amperes 



From these equations it is evident that the 
current varies directly with the voltage and in- 
versely with the resistance, — if the voltage be 
doubled, twice the current will flow, etc. ; if the 
resistance be doubled, half the current will flow. 

The resistance varies directly with the volt- 
age and inversely with the current. 

The voltage varies directly with the current 
and directly with the resistance. 

This law is the fundamental principle in most 
electric calculations. 

E is generally symbolic of voltage, C of cur- 
rent, R of resistance. 

E = CXR. 



The Cleaning and Electro- Plating of Metals 



CLEANING THE WORK. 
The Use of O. P. C. 

The term cleanliness, when applied to metal 
surfaces which are to be plated, means absolute 
freedom from the least trace of dust, grease, 
oil, rust, corrosion, tarnish, or any form what- 
ever of foreign matter. A surface made clean 
by any mechanical means alone, will not serve 
for electro-plating because of loose metal dust, 
and particles of polishing material or lubricant 
left on the work. A perfectly clean surface 
once touched with the hand is no longer clean 
and will peel or strip where touched. Articles 
to be plated usually have their surfaces pre- 
pared first by mechanical means — as buffing — 
and are then made chemically clean by suitable 
solutions. Each metal requires slightly differ- 
ent treatment and the treatment varies to some 
extent with the nature of the abrasive, grease, 
oil or dirt to be removed. 

Lye and caustic have long been used for 
cutting greases and oils. But on some they 
work very slowly, and in all cases they are dis- 
agreeable and dangerous to work with and have 
a detrimental effect on soft or tarnishable 
metals. There are many cleaning compounds 
available at the present time which give very 
efficient service on certain grades of work. In 
the majority, however, some desirable features 
have been sacrificed to enhance the value of 
others. 



4 The Cleaning and Electro- Plating of Metals 

Oakite Platers' Cleaner has been scientifically 
compounded, to combine the valuable qualities 
of the best cleansing- agents and in it, all objec- 
tionable and detrimental features are eliminated 
or nulUfied. When properly used, O. P. C. in- 
sures a chemically clean base metal in unusually 
short time, avoids discoloration of metal, and 
provides better working conditions and elimi- 
nates danger to the workmen. O. P. C. will not 
''lead plate" on soldered articles. O. P. C. con- 
tains no filler and dissolves completely in 
water. It contains no inert material; every 
ounce is pure, effective concentrated cleaner of 
great lasting power, due to the fact that its 
action is physical rather than chemical, as with 
most cleaners. Every atom cleanses. For these 
reasons, the use of O. P. C. assures the mini- 
mum operating costs for the cleaning processes, 
and aids the other departments by avoiding the 
necessity of rebuf^ng, etc., and by decreasing 
the percentage of imperfect work. 

The tank containing the cleaning solution 
should be equipped with a steam coil placed 
at the side nearest the workman, and should 
have a bottom draw ofif. When the steam coil 
is on the near side of the tank, the rise of w^ater 
from it, by convection currents, continually 
sweeps across the surface and so keeps all float- 
ing oil and dirt at the further side. The steam 
coil should never be in the bottom of a tank. 
In this position it makes the cleaning out of a 
tank a very troublesome and dirty task. 



The Cleaning and Electro-Plating of Metals 5 

After coming* from a cleaning tank, the work 
should be well rinsed in clean cold water; con- 
tinual running water in the rinse tank is advis- 
able. After rinsing notice whether the water 
wets the whole surface of the work evenly, and 
will run ofif without breaking-. This indicates 
a clean surface. 

The electric cleaner is important, and is 
largely used under certain exacting conditions. 
Its use gives a chemically clean surface in a 
shorter time than by the ordinary method, and 
it diminishes tarnish on tender work. O. P. C. 
is without doubt the only Electric Cleaner that 
will give a chemically clean surface without the 
use of cyanide. The solution should be made 
up with 4 to 6 ounces O. P. C. to the gallon, 
depending on the work to be cleaned. The 
temperature should be at the very least 200° F,, 
and a direct current of about 6 volts should 
be used. The current density should' run about 
50 amperes per sq. foot ; O. P. C. makes an 
electrolyte of high conductivity and in small 
amount will easily let this current pass. 

Sometimes on difficult work it is well to use 
a double throw switch and run direct current 
for a short time, then reverse for a few mo- 
ments, and then finish with direct current. 

The iron tank may be used as the anode, with 
the regular insulated frame and rod on top to 
take the work. It is better practice, however, 
to use sheet iron anodes about 6 inches wide. 
Rheostats are in most cases unnecessary, as high 
amperage is desired. 



6 The Cleaning and Electro- Plating of Metals 

The current density should never be allowed 
to rise above 50 amperes per sq. ft., however (as 
might happen in a small tank where the elec- 
trodes are close together, or where a very 
strong solution affords unusually high conduct- 
ance). Too much current will iDurn the grease 
or dirt on to the work and hinder, rather than 
facilitate its removal. In any case where this 
occurs, the use of a rheostat to cut down the 
current to a proper value, will remedy the 
trouble. 

On soft metals the use of an electric cleaner 
is highly advantageous, as its use largely dimin- 
ishes tarnish and pitting. 



OTHER CLEANING AGENTS. 

The combination of mineral salts, known as 
Oakite, in the form of a dry white powder, is 
too well known to need much description. It 
is the basis of all Oakite compounds; it contains 
none of the acids, tyes, sodas or caustics. It 
cleans by a purely physical action, being solely 
an emulsifying agent; and by avoiding sapon- 
ification, the Oakite cleaners have a much 
longer life and act much more speedily than 
others. It is a very free rinser, a good elec- 
trolyte, and harmless to skin, fibres or metals. 

There are some cases where a different or 
modified action is necessary from that of the 
O. P. C. cleaning bath. 

For these special cases a specially developed 



The Cleaning and Electro- Plating of Metals 7 

product is available as Oakite Composition 
No. 1, and Oakite Composition No. 2. 

Oakite Composition No. 1 is a high-grade 
soap compound, carefully compounded for its 
specific purpose. It is made for cleaning 
aluminum and to supplement Oakite in the 
cleaning of soft metals, and for the removal of 
tripoli and rouge buffing from plated ware. 

Oakite Composition No. 2 is a high-grade 
soap compound, similar to the No. 1 composi- 
tion, but is much stronger in its action. It is 
used to supplement Oakite and O. P. C. and is 
specifically used for the following problems : 

Removing smuts, heavy oils and greases from 
metals ; removing sand-buffing material ; remov- 
ing burnt on oil, difificult japan, enamel, paint, 
shellac, varnish, etc. 

A cold rinse, not a hot rinse, should follow 
cleaning in either soap compound, which may 
then be followed by a hot rinse if it is desired 
to make the work self-drying. 



CLEANING BEFORE PICKLING. 

Before the use of any pickle to remove scale, 
rust, corrosion, or tarnish from any metal, it 
should first be given a dip of 1 to 3 minutes in 
hot O. P. C. solution 8 oz. per gallon, followed 
by a rinse. The purpose of this is to prepare 
the surface for the action of the acid, by remov- 
ing all foreign matter, such as oil, grease, and 
dirt, on which acid has no effect, and which 
would retard the pickle and make it uneven in 



8 The Cleaning and Electro- Plating of Metals 

effect, and result in waste of acid and metal. 
This effects great saving in time and in acid 
bills; usually to the extent of 50% in large 
installations. 



CLEANING CAST IRON STOVE WORK, 
ETC. 

O. P. C 8 Ounces, 212° F. 

Water 1 Gallon. 

For upkeep, add about 2 ounces O. P. C. per 
gallon per week, or as required. Time required 
for cleaning this class of work about 5 minutes 
in this solution. Then rinse in cold water and 
scrub with pumice. Repeat cold water rinse, 
then put in acid pickle (I part HCl, 8 parts 
HoO). Then into cold water rinse and transfer 
to plating solution. 

Scrubbing- with pumice can be eliminated on 
this class of work by using two cleaning tanks. 
First place work in tank made up as follows : 

O. P. C 4 Ounces, 212=^ F. 

Oakite Composition No. 2.. 4 Ounces. 

Ammonia ^ Ounce. 

Water 1 Gallon. 

Then rinse in hot water. Then into O. P. C. 
tank, then cold water rinse, then into acid 
pickle. Then repeat cold water rinse and 
transfer to plating bath. 



CLEANING LEAD AND ANTIMONIAL 
ARTICLES. 

Use O. P. C. 6 ounces to gallon water. Keep 
boiling by steam coil. For upkeep add 1 to 2 



The Cleaning and Electro-Plating of Metals 9 

ounces per gallon per week or as may be 
necessary. Time required for cleaning- this class 
of work is from 3 to 5 minutes in still tank. 



ELECTRIC CLEANER ON LEAD AND 
ANTIMONY. 

O. P. C 4 Ounces, 200° F. 

Water 1 Gallon. 

Use direct current of about 6 Volts. Time 
required in this solution from 1 to 2 minutes ; 
then rinse in cold water and transfer to plating 
bath. 



CLEANING BRASS, COPPER OR 
GERMAN SILVER. 

O. P. C 6 Ounces, 200^ F. 

Water 1 Gallon. 

The upkeep is very small, depending upon 
the quantity of work turned out. Can be used 
with or without the electric current. Will not 
discolor or tarnish. Time required 1 to 3 min- 
utes. In a still bath, the addition of one fluid 
ounce of ammonia daily, for every 10 gallons 
of solution is helpful in keeping the work 
bright. 

PREPARING TIN FOR NICKEL PLATING. 

The best method is to use the Electric Clean- 
er, with direct current of 6 to 8 Volts. 

O. P. C 6 Ounces, 200° F. 

Water 1 Gallon. 

Time required to clean this class of work in 
this solution 1 to 2 minutes. Then rinse in cold 



10 The Cleaning and Electro-Plating of Metals 

water and transfer to nickel bath. In some 
cases, where the work is of unwieldy, large 
pieces, it would be advisable to just dip in a 
regular O. P. C. bath, 8 ounces to gallon water, 
200° F. Then rinse in cold water, then scrub 
with lime or pumice. Then rinse in cold water 
and transfer to nickel tank. 



CLEANING OF DIE CASTING METAL FOR 
PLATING. 

Place in solution of: 

Water 1 Gallon, 160° F. 

O. P. C 4 Ounces. 

With or without electric current. Time re- 
quired to clean this metal, with electric current 
(direct) 1 minute, then reverse >^ minute ; 
without electric current about 3 minutes. 



JEWELRY. 

Cleaning off and Removing Shellac : 

To clean, place in solution of: 

Water 1 Gallon, 160° F. 

Oakite Composition No. 1. . . .^ Ounce. 

Ammonia 1 Ounce. 

Time required in solution, to clean thorough- 
ly, 1 to 3 minutes. 

Removing Shellac: 

Place in solution of: 

O. P. C 4 Ounces. 

Water 1 Gallon, 160° F. 

Time required 15 minutes. 



The Cleaning and Electro-Plating of Metals 1 1 

In some factories the line of work which is 
manufactured is such that the electric cleaner 
is far superior to any other, but in 75% of the 
factories it would be much better to put in the 
two tank cleaning system. 

Tank No. 1: 

O. P. C 4 Ounces, 200° F. 

Oakite Composition No. 2. . . 4 Ounces. 

Ammonia 54 Ounce. 

Water 1 Gallon. 

Then rinse in hot water and then place in 
Tank No. 2: 

O. P. C 8 Ounces, 200° F. 

Water 1 Gallon. 

Just a minute in each of these solutions will 
clean almost anything well enough to plate 
without scrubbing. In very few cases would 
scrubbing be necessary. 

ELIMINATE CYANIDE. 

Where a plater has a line of polished brass 
or copper to nickel plate, by cleaning this work 
in O. P. C. 6 ounces to gallon water, 200° F., 
he can make a great saving on cyanide by using 
muriatic acid, 10% solution, in place of a cyanide 
dip, as there is but slight discoloration of the 
metal when using O. P. C. 

CLEANING BEFORE GALVANIZING. 

Use O. P. C. 8 ounces to gallon water. Keep 
boiling by steam coil and allow work to remain 
in this solution about 3 to 5 minutes ; then rinse ; 
then place in acid pickle; then rinse in cold 
water; then transfer to galvanizing bath. 



12 The Cleaning and Electro-Plating of Metals 

If electric current is used 6 ounces O. P. C. 
to gallon water will give same results in 1 to 2 
minutes' time. 

STOPPING OFF. 
Stopping Off: 

If certain parts of a metallic object are not to 
receive a deposit, as for instance, when a con- 
trast is to be effected by depositing different 
metals in a pattern upon the same object, these 
parts are covered or stopped off with a varnish 
or wax. Stopping off varnish is prepared by 
dissolving asphalt, or damar with an addition 
of mastic, in turpentine. It is appHed with a 
brush and allowed to dry thoroughly and then 
hardened in cold water. After plating, the 
''stop" is easily removed with O. P. C. 8 ounces 
per gallon or if asphalt, with O. P. C. and 
Oakite Composition No. 2, 4 ounces of each 
per gallon. 

Removing White Lead and Red Lead: 

Make up solution of: 

O. P. C 8 Ounces. 

Water 1 Gallon, 212° F. 

Place work in solution for 3 to 5 minutes, 
then brush with hand brush, then rinse in cold 
water. Oakite Composition No. 2 is sometimes 
needed if it has set very hard. 

Removing Lacquer or Enamel: 

The ordinary lacquers such as are being used 
on brass chandeliers, etc., can be removed in 



The Cleaning and Electro-Plating of Metals 13 

O. P. C. solution 8 ounces to the gallon of 
water 212° F. Time required for removal in 
most cases is 1 to 3 minutes. Where lacquer 
has been baked on with considerable heat it is 
an advantage to use O. P. C. and No. 2 Com- 
pound in these proportions : 

O. P. C 6 Ounces, 212° F. 

Oakite Composition No. 2. . . 6 Ounces. 

Water 1 Gallon. 

This will remove some enamels or lacquers 
in a few minutes. However, the better grades 
of lacquers or enamels, which are baked, wnll 
take from H to 1 hour. 



STRIPPING. 

This term is employed to denote not only an 
accidental loosening of the deposited metal, 
under the scratch brush or burnisher, but also 
an intentional removal of a deposit by means 
of acid. 

All work must be carefully cleaned (and any 
lacquer or similar protective coating must be 
removed) before stripping, in the same manner 
as for plating, using O. P. C. 8 ounces per gal- 
lon. A uniformly clean surface is necessary, to 
allow the acid to act evenly. 

Silver is stripped from old plated work on 
copper and its alloys, before they can be re- 
plated, by immersing the plated article in hot 
concentrated sulphuric acid, and adding from 
time to time a few crystals of saltpeter. The 



14 The Cleaning and Electro- Plating of Metals 

acid must be made hot, the articles to be 
stripped must be quite clean and dry before 
immersion, and must be moved about while 
adding the saltpeter. If this is done as directed, 
the whole coat of silver may be loosened with- 
out serious damage to the metal beneath. The 
same operation may be performed in a cold 
mixture, composed of 1 part strong nitric acid 
added to 10 parts of sulphuric acid in a stone- 
ware vessel. The goods to be stripped, in these 
acids should be first attached to stout wires, 
as they must be frequently moved about in the 
solution, and taken out to be examined from 
time to time, to prevent overdoing the process 
and injuring the metal beneath the coat. When 
all the silver has been stripped off, the article 
must be at once rinsed in clean water to free 
it from acid; but should it be necessary to re- 
immerse the article, it must be first dried, since 
the presence of water in the acid will cause it to 
attack the metal beneath the coat of silver. 
When the plated article is made of iron, steel, 
zinc, pewter, lead, or white metal, it must not 
be immersed in the stripping acid, but should 
be desilvered in a solution of cyanide of potas- 
sium by means of a current from a battery or 
a dynamo. An old disused plating solution will 
do very well for this purpose if it has plenty of 
free cyanide. Immerse the article to be stripped, 
and connect it as an anode to the positive pole 
of the battery or dynamo, and suspend a plate 
of carbon or a strip of platinum foil in the solu- 
tion as a cathode. Then pass a strong current 



The Cleaning and Electro-Plating of Metals IS 

until all the deposited coat of silver has been 
dissolved. Gold may be removed from gilded 
articles by a similar method in an old gilding- 
solution. Gold may also be stripped from base 
metals by immersing them in hot nitric acid 
and adding some common salt as required. This 
operation is similar to the acid process for strip- 
ping silver, and needs equal care. Nickel 
is stripped from nickel-plated articles in a mix- 
ture composed of 1 pint of water, 1 pint of 
strong nitric acid, and 4 pints of strong sul- 
phuric acid. The water must be first placed in 
a lead-lined vessel, or in one of enameled iron, 
and the sulphuric acid added gradually and 
carefully, as the addition of this acid to water 
raises its temperature to a boiling point. When 
the sulphuric acid has been mixed with the 
water, the mixture must be poured into a stone- 
ware dipping pan and the nitric acid added. 
These precautions are necessary, because the 
mixture of the two acids and water will dissolve 
lead and enamel, but will not pierce acid-proof 
stoneware, whilst this in turn will not stand 
sudden expansion caused by the heat generated 
in mixing the sulphuric acid with water. All 
operations in stripping by acids must be per- 
formed in the open air, or under a hood with 
good draft. The process must be closely 
watched throughout and the article immediately 
removed, once its coat has been stripped off. 
The time required for stripping runs from a few 
minutes to half an hour. 



16 The Cleaning and Electro-Plating of Metals 

ELECTRICAL REQUIREMENTS 
NECESSARY IN A PLATING ROOM. 

In the first place it is better to buy a first 
class dynamo ; even though it be a little 
more expensive in the beginning, it will prove 
to be the cheapest in the end. The dynamo 
should be set up on a good solid foundation 
and as near to the tanks as convenient, and 
should be placed so that the plater will have 
easy access to all its working parts. A few 
minutes' attention given to the dynamo each 
morning adds greatly to efficiency, and will 
keep commutator and brushes in good condi- 
tion. Be sure the dynamo rests firmly on its 
foundation. Great care should be taken in ad- 
justing the brushes not to have too much pres- 
sure on commutator. The brushes should not 
bear too hard on commutator, but just enough 
to insure perfect contact between brush-holder 
and rod. If commutator shows signs of rough- 
ness, smooth with fine sand-paper, and lubricate 
with vaseline. Never use emery paper. The 
conducting bars running from the dynamo past 
the various tanks in the plating room should 
be large enough to carry all current that the 
dynamo gives without heating, and the various 
vats can be connected by means of wires or 
rods leading from the conducting bars. Great 
care should be taken to have the wires of a 
sufficient size so as not to lose too much power 
in overcoming resistance. The current must be 
regulated for each tank by a resistance switch 



The Cleaning and Electro-Plating of Metals 



17 




18 The Cleaning and Electro-Plating of Metals 

or rheostat connected to the positive bar and 
also to the positive bar of the tank. Rheostats 




Fig. 2 — Electro-plating Dynamo. 
Manufactured by General Electric Company, Schenectady, N. Y. 



are put up as near to the tank as possible, and 
should be shut off while putting work into tank, 
and then be turned toward the strongest point 
until a suitable current is obtained. 



The Cleaning and Electro-Plating of Metals 



19 



It is quite essential in a large plating room 
to have a voltmeter, and also an ampere meter, 
which will show the plater the exact amount 




Fig. 3 — Ammeter for Electro-plating Work. 
Manufactured by Weston Electric Company, Newark, N. J. 

of current he is getting. By means of an ac- 
curate ammeter, the amount of metal actually 
deposited can be determined. 



NICKEL PLATING. 

The solution should be made up by dissolv- 
ing % of a pound of nickel-ammonium sulphate 



20 The Cleaning and Electro-Plating of Metals 

(double nickel salts) in 1 gallon of water, which 
will bring the density up to about 6° or 7° Be, 
and adding a small amount of boric acid, mak- 
ing a fine, bright nickel. In some instances, 
agitated solutions are of great importance, for 
the reason that a higher current density may 
be used, and so decrease the time, prevent pit- 
ting ; the work will come out just as bright as in 
a still solution. 

Anodes : Anodes are very important in nickel 
solutions, owing to the fact that the solution 
does not readily dissolve the metal, as this 
action takes place only by the aid of the cur- 
rent, and as nickel sulphate will not conduct 
electricity easily, and as ammonium sulphate 
wnll, we have combined them and make the 
double salt, and the free sulphuric acid liberated 
by the deposition immediately passes to the 
opposite pole, and attacks the anodes. A large 
anode surface is necessary. Cast anodes are 
preferable, as rolled anodes are so hard that 
more current is required. 

Bath: The bath should be slightly acidic. 
This condition can be readily told, by testing 
with litmus paper. Blue litmus paper is colored 
red by acid, and red litmus paper is colored blue 
by an alkali. Too much acid will cause peeling, 
and if the bath is alkaline a dark deposit will be 
obtained. The solution should be kept always 
at 6>4 to T'^ Be. 



The Cleaning and Electro-Plating of Metals 21 




II 



22 The Cleaning and Electro-Plating of Metals 

To Plate Nickel on Aluminum. 

Polish, clean (using No. 1, 2 ounces per gal- 
lon), followed by Oakite (j4 ounce per gallon), 
rinse in cold water, dip into concentrated nitric 
acid, rinse in cold water, dip into: water, 1 
gallon ; iron chloride, 1 ounce ; muriatic, ^ 
ounce ; and from this dip rinse quickly and place 




Fig. 5 — Voltmeter used in Electro-plating. 
Manufactured by Weston Electric Company, Newark, N. J. 



directly in nickel solution. Plate with heavy 
current for 2 minutes, and then reduce current. 
Nickel solution: water, 1 gallon; single nickel 
salts, 8 ounces; Epsom salts, 3 ounces; boric 
acid, 1 ounce; common salt, ^ ounce. Plate 
with 4 volts at 80° F. 



The Cleaning and Electro-Plating of Metals 23 

COPPER PLATING. 

Copper Solution: 

Warm water 1 Gallon. 

Sodium cyanide 96/98% 3>4 Ounces. 

Copper cyanide 70% 3 Ounces. 

Soda ash 58% 2 Ounces. 

Sodium hyposulphite 54 Ounce. 

Copper cyanide contains 70% metal and 30% 
cyanogen, so a solution prepared as above will 
contain 2.1 ounces of copper in the form of 
metal per gallon of solution. If dense solutions 
are required the metal content may be increased 
3/^ to 4 ounces per gallon with the other 
materials in proportion. In replenishing copper 
solutions \vith copper cyanide the following 
proportions will equal 2 pounds of sodium 
cyanide and 1 pound of copper carbonate: 

Hot w^ater 2 Gallons. 

Sodium cyanide 12 Ounces. 

Copper cyanide 11 1/3 Ounces. 

Soda ash 58% 4 Ounces. 

Copper carbonate consists of 50 per cent, 
metal and copper cyanide consists of 70 per 
cent, metal. 



To Plate Copper on Aluminum. 

Polish, clean, dip in hot O. P. C. (^ pound 
per gallon), rinse and immerse few moments 
in 5% hydrofluoric acid solution. Shake acid 
from work Avell, and plate directly. Bath : water, 
1 gallon : copper sulphate, 1^ lbs. ; sulphuric 
acid, 2 ounces ; black molasses, % ounce. Use 



24 The Cleaning and Electro- Plating of AIetals 



wooden, or lead, or asphaltum lined container 
for hydrofluoric acid. 



COPPER PLATING AND CLEANING IN 
SAME SOLUTION. 

Water 24 Gallons. 

O. P. C 12 Pounds. 

Copper Cyanide 12 Ounces. 

Sodium Cyanide 24 '* 

First, dissolve the O. P. C. in the water; sec- 
ond, take up the copper cyanide with the 
sodium cyanide ; third, add the copper and 
sodium cyanide to O. P. C. 

Use an iron or steel tank. Keep boiling with 
steam coil near side of tank. Use copper 
anodes and from 6 to 8 volts pressure. 



BRASS PLATING SOLUTION. 

The brass plating solution seems to be the 
most difficult of all solutions to handle, and 
there are several ways of running a brass 
solution for various kinds of work, and if a 
man has had a little experience in brass plating 
he will readily understand what kind of a solu- 
tion is needed for the work he is about to plate. 
In my experience I have used several different 
brass solutions, and have plated several kinds 
of metals in difTerent lines of work, and I find 
that in plating lead work or any white metal, 
that a solution made up of about 

Warm water 1 Gallon. 

Sodium cyanide 96/98% 9 Ounces. 



The Cleaning and Electro-Plating of Metals 25 

Copper cyanide 70% 5 Ounces. 

Zinc cyanide 55% 2 Ounces. 

Soda ash 58% 4 Ounces. 

Ammonium chloride 1/3 Ounce. 

with a small amount of white arsenic dissolved 
in caustic soda, and a small quantity of am- 
monia, will bring very good results. 




Fig. 6 — A Rheostat used in the Plating Room 

In preparing the solution use one-third of the 
total capacity of the tank in gallons, heat to a 
temperature of 120^ F. ; first, add the cyanide, 



26 The Cleaning and Electro-Plating of Metals 

then copper, then zinc and soda ash and finally 
balance of cold water to make up the quantity 
of the solution required. Finally add the 
chloride of ammonium. Mix thoroughly and 
electrolyze the solution. 

Care should be taken in using the arsenic, 
not to add too much. A very small amount is 
sufficient, and when this solution is tried, if it 
does not work nice and clear, simply add a 
little more ammonia. 

In replenishing brass solutions proportions 
given for copper solution may be used very 
satisfactorily. The successful brass plater uses 
very little zinc in his solutions when once 
prepared. Very small proportions of caustic 
soda or aqua ammonia (^4- ounce per gallon) 
will keep a permanent reduction of the zinc in 
solution with small additions of zinc cyanide. 

The addition of free cyanide to a solution 
should be determined by anode conditions. 
Never add more than ^ ounce of cyanide as 
free cyanide per gallon of solution at any one 
time. 



ZINC PLATING. 



The electrolyte or zinc solution can be made 
up from sulphate of zinc (white vitriol) or from 
chloride of zinc, or from a combination of the 
two. An addition of conducting salts, such as 
sulphate of sodium, sulphate of aluminum, 
chloride of ammonium, etc., can be used to in- 
crease the conductivitv of zinc solutions. There 



The Cleaning and Electro- Plating of Metals 27 

are also a number of organic and inorganic 
chemicals recommended for the purpose of 
producing a more dense and brighter deposit. 
The majority of these chemicals act as a colloid. 
The following solution has been worked with 
success in an open still tank : 

Zinc sulphate 200 Ounces. 

Sulphate of sodium (crystals) .... 20 Ounces. 

Sulphate of aluminum 10 Ounces. 

Boric acid 3 Ounces. 

Water to make 7 gallons. 

An addition of a few ounces of zinc chloride, 
or instead an ounce of hydrochloric acid, will 
improve the solution to some extent ; also an 
addition of grape sugar will improve a sulphate 
of zinc solution and produce a smoother and 
more uniform finish. 

The above solution can be successfully used 
for all kinds of articles, including wire, band 
iron, sheets and wire cloth, and will produce by 
three volts and about twenty amperes per 
square foot a white, smooth deposit in thirty 
minutes which will stand three one-minute 
copper tests. 

Chloride of zinc solutions can also be used 
to better advantage in open tank work, as well 
as in mechanical plating machines. A good solu- 
tion is composed of the following: 

Zinc chloride 10 to 15 Pounds. 

Chloride of ammonia 5 to 7.5 Pounds. 

Grape sugar 1 Pound. 

Water to make 10 Gallons. 



28 The Cleaning and Electro- Plating of Metals 

In the open bath a low potential is used, about 
3 volts being required with a current of 12 to 15 
amperes per square foot of work surface, the 
density of the solution being about 20° Baume, 
although a higher voltage can be used if it is 
desired to shorten the time of deposit. For 
mechanical apparatus, where a revolving con- 
tainer is used, the solution is brought to a 
density of 25° to 30° Baunie and 8 to 10 volts 
are used, with a corresponding increase in 
current. 



PLATING ON ALUMINUM. 

In plating aluminum, one method is to dip in 
5% hydrofluoric acid after cleaning, then into 
a mixture of 100 parts of sulphuric, 75 parts 
nitric acid (both concentrated). After rinsing 
with water, the surface is immediately plated 
with zinc, on which any other metal may be 
plated. 



The Cleaning and Electro-Plating of Metals 29 






Fig. 7 and 8 — Two Views of the Patent Automatic Moving Plating 

Tank manufactured by the U. S. Electro-Galvanizing Company, 

Brooklyn, N. Y. 



30 



The Cleaning and Electro- Plating of Metals 



TUMBLING BARREL PLATING. 

Tumbling barrels have almost entirely done 
away with wiring or basket plating for small 
work such as screws, collar buttons, etc.. and 
at the present day they turn out this class of 




Fig. 9 — The U. S. Junior Plating Barrel made by the 
U. S. Electro-Galvanizing Company, Brooklyn, N. Y. 



work in tumbling barrels in large quantities 
and in this way reduce the cost to a much 
smaller figure than when it was done by the 
old method. 



The Cleaning and Electro-Plating of Metals 31 

A very good brass solution for tumbling 
barrel plating is made as follows : 

Water 1 Gallon. 

Sodium cyanide 96/98% 15 Ounces. 

Copper cyanide 79% 8 Ounces, 

Zinc cyanide 55% 4 Ounces. 

Soda ash 58% 6 Ounces. 

Caustic soda 78% 1 Ounce. 

Aqua ammonia in amounts of j^ ounce and 
upwards may be used to bring up a uniform 
brass deposit. Prepare the solution in the order 




Fig. 10 — Another View of the U. S. Junior Plating Barrel. 

given and the replenishing should be accom- 
plished on a similar basis. Ammonia and arsenic 
may be added in small proportions to brighten 
deposits as required. 



32 The Cleaning and Electro-Plating of Metals 

SILVER PLATING CASKET HARDWARE. 

The work is first wired or racked up, then it 
is dipped in the O. P. C. and rinsed off in clean 
Avater, nicked plated for about five minutes, 
rinsed in clean water, put into the silver strike 
solution for a minute or two, then into the 
bright silver solution, where it is usually run 
for about five minutes. This class of work must 
come out of the silver solution bright and clear, 
and without stain, as some of the cheap work 
goes through without any buffing, and the work 
that is to be buffed has to be done simply by 
color bufffng. When the Avork comes out of 
the silver solution it should be rinsed in cold 
water and then in hot water, and then hung in 
an oven at 150 to 200° F. until thoroughly dry. 
It is then ready for buffing. The O. P. C. solu- 
tion for this class of work should be made up as 
follows : O. P. C, 4 ounces to gallon water, 
with electric current at about 6 to 8 volts pres- 
sure. 

The nickel solution should be made of Ya 
pounds of double nickel salts to a gallon of 
water, and should stand about 6° to 7° Be. A 
small amount of table salt added to this solution 
occasionally will whiten the deposit. The silver 
strike solution should be made up of about 10 
ounces cyanide of sodium to the gallon, and 
y2 ounce silver chloride to a gallon of water. 
The silver solution should contain 2 ounces of 
silver chloride and about 12 ounces of cyanide 
of sodium per gallon of water; add bisulphide 



The Cleaning and Electro-Plating of Metals 33 



of carbon in the usual manner to brighten de- 
posit. Care should be taken in adding- this 
brightener, as too much will give very bad 
results. A few drops of the bisulphide of car- 
bon just as purchased, without dissolving at all, 
added to a silver solution each morning, — stir 
the top of solution and repeat at noon when 
using solution all the time, — is better than any 
other method for this line of work. 



SILVER PLATING STEEL KNIVES. 

The knives are first placed in a basket, and 
then washed in a solution of O. P. C, 4 ounces, 
and Oakite Composition No. 2, 4 ounces, to 
gallon of water boiling, then hot and cold water 
rinsed, then placed in a solution of Oakite (4 
ounces to the gallon) to prevent rust, and 
scoured with fine pumice, rinsed in clean water 
and racked up. 

Then dip in dilute sulphuric acid dip in pro- 
portion of 1 part of acid to 8 parts of water, 
then rinse in clean water and hang into a steel 
strike. The steel strike is made up of 

Carbonate of copper 10 Grains. 

Chloride of silver 5 '' 

Cyanide of sodium 10 Ounces. 

Water 1 Gallon. 

Use copper anode 2x8 inches in cloth bag. 

Silver " 1 inch square. 

It is advisable at the end of each week to 

take out about 1 gallon of the strike solution 

and add about 1 quart of silver solution and 

cyanide enough to keep the solution standing 



34 The Cleaning and Electro-Plating of Metals 

10 Be. Never add any copper to the strike 
after first making, as all the copper required is 
obtained from the anode. After striking the 
knives in steel strike, they should be rinsed 
in clean water, and struck up in the regular 
silver strike, and from there into silver solu- 
tion. The silver solution should always stand 
about 15° to 18° Be, and have 1 to 1>^ ounces 
of chloride of silver per gallon, and 15 to 20 
ounces of cyanide of sodium per gallon. It 
is best to keep the knives in motion while 
plating by means of a swing frame attached 
to the negative pole, which is the plating pole. 
A scale attachment w^hich will register the 
amount of silver being deposited can also be 
obtained. 

SILVER PLATING HOLLOW WARE. 
Brass, Copper, or German Silver. 

The work is first placed in O. P. C. solution 
8 ounces to gallon water kept boiling with a 
steam coil. Time required in cleaning solution 
about 1 to 3 minutes. Then rinse in cold water, 
scour with fine pumice on a tampico brush or 
wheel, allowing a steady drip of water to flow- 
on the brush while the work is being scoured, 
so as to keep work wet, then sponge ofT thor- 
oughly in clean water and hook or wire up, 
when it is ready for plating. The work is then 
hung in a clean water vat until the plater is 
ready to handle it. On removal, dip work in 
O. P. C. solution, 6 ounces to gallon water, 
200° F. Then cold water rinse, then into mer- 



The Cleaning and Electro-Plating of Metals 35 

cury dip, rinse in clean water and then dip in 
O. P. C. solution. Then into a weak cyanide of 
sodium dip and from this into silver strike solu- 
tion, where it is struck up for a few minutes, 
and then into silver solution, where it remains 
until the desired amount of silver is deposited. 
This method is for work that is satin-finished 
or burnished. 

If the work is only to be buff-finished, a dif- 
ferent method should be used in cleaning, as 
this class of work is only burnished on such 
parts as cannot be readily reached by the buff. 
Therefore use a solution of O. P. C. 6 ounces 
to gallon of water 200° F. Place work in 
O. P. C. solution for about 2 minutes, wash 
off with a Canton flannel brush, scour only such 
parts as inside of tea pots, or under handle, etc. 
Then plate in a bright silver solution. For 
satin-finish or burnished work it is best to use 
a solution composed of 

Water 1 Gallon. 

Silver cyanide 80>^% 2i^ to 3>^ Ounces. 

Sodium cyanide 96/98% 3)4 to 5^4 Ounces. 

Bright Silver Solution: 

Water 1 Gallon. 

Silver cyanide 80^% }i to 2% Ounces. 

Sodium cyanide 6 to 8 Ounces. 

The metal content of silver solutions may be 
varied from ^ ounce metallic silver to 6 ounces 
per gallon of water for quadruple plate upon 
britannic goods. Ordinary silver solutions for 



36 The Cleaning and Electro-Plating of Metals 

brass goods average 2 ounces metal per gallon 
of water. 



SILVER PLATING LEAD OR SPELTER 
ARTICLES. 

The best results can be obtained by first 
washing the articles in a solution of O. P. C. 
4 ounces and Oakite Composition No. 2, 4 
ounces, to gallon water, 200° F. Time required 
to clean in this solution 1 to 3 minutes. Then 
rinse in hot water ; then they should be hooked 
or racked up and dipped in the O. P. C. solution 
of 6 ounces O. P. C. to gallon water 200° F. 
Then rinse in cold water, and strike in cyanide 
copper solution for a couple of minutes, and 
nickel plate about Yz hour. Then rinse in clean 
cold water, dip in O. P. C. solution and then 
cold water rinse, then place in silver strike solu- 
tion, for a couple of minutes, and plate in the 
ordinary silver solution until the desired amount 
of silver is deposited. The reason for nickel 
plating is only to save silver. For instance, 
when an article for French Gray finish is re- 
lieved, one is liable to cut through on some 
little part, and if a nickel base is under the silver, 
it in most cases would not be noticed. 



ARGENT IVORY OR SILVER WHITE. 

This is an exceptionally fine white finish, 
burnished on certain parts, and is produced in 



The Cleaning and Electro-Plating of Metals Z7 



the silver solution by running the work just 
long enough to get a dead white, and rinsing 
in cold and hot water, and then in cold again, 
and dry in soap suds or alcohol, and then burn- 
ish using Okemco Burnishing Soap (one lb. to 
8 gallons of water) for the burnishing. In this 
way one is not so liable to stain the work. Or 
burnish dry, which in some cases is preferable 
as this finish stains very easily. This white 
finish should be lacquered with a pure white 
celluloid lacquer. 



OLD IVORY FINISH. 

This is a beautiful finish, and can be pro- 
duced in several ways. One can get a very 
fine finish by using white enamel lacquer and 
spraying it on the work, and when dry apply 
with a camel's hair brush, burnt umber ground 
with oil and thinned with turpentine until the 
shade desired is obtained. A small amount of 
burnt umber to about 6 to 8 ounces of turpen- 
tine will give a fine tan color, which is a very 
fine color to apply on the white. Rub off with 
turpentine with a small piece of felt or chamois. 
A still better way to produce this Old Ivory is 
to produce the white in the silver solution, run 
the work just long enough to get a dead white, 
and then rinse off in cold and hot water, and 
then in cold water, and then dry in alcohol or 
soap suds and lacquer. Apply burnt umber as 
before. 

For the cheap class of work the cost of this 
finish can be reduced by first running the work 



38 The Cleaning and Electro-Plating of Metals 

in an acid copper solution for about ^ hour 
which will give a dead finish. Then silver 
plate. In this way the dead white is produced 
in about half the time in silver solution, thus 
saving silver. 



ROSE GOLD. 

Rose gold finish is a beautiful finish on almost 
any kind of work. There are several ways of 
producing this finish. For instance, if one wants 
a line rose finish on high class jewelry, one can 
produce the smut by the use of an old gold 
solution, to which may be added a small amount 
of caustic potash, and use carbon anodes. I 
have found that adding carbonate of copper 
taken up with yellow prussiate of potassium in 
small quantities will give a very fine red rose. 
Run work in this solution for a couple of min- 
utes, then rinse in a weak cyanide of sodium 
dip, then relieve with bi-carbonate of soda, and 
then run into a roman gold solution, which 
consists of 

2 Ounces of C. P. cyanide of sodium, 

1 Gallon of water, 

5 Pennyweights of fulminate of gold. 
For cheap classes of work one can produce 
a rose finish which is very inexpensive, and 
which is also a very nice finish by producing 
the smut in an acid copper solution, and then 
relieving with bi-carbonate of soda, and gold 
plating in a roman gold solution. I have also 



The Cleaning and Electro-Plating of Metals 39 

had success by using a dip gold solution made 
up of 

1 Gallon of warm water, 

5 Pennyweights fulminate of gold, 

2 Ounces C. P. cyanide of sodium, 
2 Ounces phosphate of soda, 

1 Stick caustic potash. 



GILDING INSIDE OF SPOONHOLDERS, 

CUPS, CREAM PITCHERS, ETC. 
Gilding Solution: 

Water 1 Gallon. 

Cyanide of sodium.. 8 Ounces. 

Fulminate of gold. . . 10 Pennyweights. 
Fill cup with gold solution and hang anode 
in cup until desired color is obtained. In a 
case such as a cream pitcher wath a lip on it, 
to gold line so that when cup is filled with 
solution it does not cover all parts' that are to 
be gilded, the proper way to gild such a piece 
of w^ork is to have a tight rubber band to place 
around the top so as to hold solution up to 
highest point in order to gild the lip, — Or use 
w^ax which by some silver concerns is called 
"Gilders' Wax." This wax should be heated 
in warm water until it becomes soft, so that it 
can be stretched out in any length or width 
desired, and placed on work while w^arm. In 
this w'ay one can gild any piece of work no 
matter what shape it may be. For instance, 
take 25 cups with an uneven surface on top, — 
heat a lump of this w^ax, enough to place over 



40 The Cleaning and Electro-Plating of Metals 

the lip of these 25 cups, and by the time the 
wax is on all of them, the first will be cool 
enough to proceed with the gilding. Then 
when all are gilded the wax should be taken 
ofif by placing in warm water, when it can be 
easily removed. Care should be taken not to 
have the water too warm. 
Gilders' Wax. 

White Wax 1 Pound. 

Rosin 2 Pounds. 

Mix by heat. 



GOLD PLATING 14 OR 18 KARAT 
COLOR ON JEWELRY. 

I have found that there is but one way to 
make these solutions, and obtain first class 
results, and that is to purchase a 14 Karat 
anode, and run the gold into a cyanide solution 
by using a porous cup until one has drawn off 
about 10 pennyweights of the anode into 1 
gallon of C. P. cyanide of sodium solution. 
Have the solution stand about 6° Be. In this 
way a beautiful 14 to 18 Karat color is obtained 
which will run very even. The richer the solu- 
tion in gold, the richer the color obtained. 
Therefore, when the solution is first made up 
with 10 pennyweights to the gallon, one will 
get about an 18 Karat color, and as the solution 
is used it will go down to a 14 Karat, and one 
can get about any shade from a copper color 
to almost a 22 Karat in this way. 



The Cleaning and Electro-Plating of Metals 41 

DARK BROWN ON COPPER OR BRASS. 

Water 1 Gallon. 

Chlorate of potash. . . 3 Ounces. 
Sulphate of copper. . . 3 '' 
Hyposulphate of soda 3 " 
Acetate of copper. .. . 3 " 
Use hot. In some cases sulphate of nickel may 

be added. 

BRIGHT FOR SILVER. 

Chloroform or ether 2 Ounces. 

Bisulphide of carbon 4 " 

Silver solution 2 Ouarts. 



GREEN GOLD. 

A very fine green gold color can be produced 
in a solution of 

10 Gallons of water, 
10 Pennyweights of fulminate of gold, 
20 Ounces C. P. cyanide of sodium, 
3 Pennyweights chloride of silver, 
2 Grains acetate of lead. 



Ormolu Gold Finish on Lead Work. 

The first thing to do is to see that the work 
is properly cleaned, and a very good way to 
clean this kind of work is to wash with a solu- 
tion of O. P. C. 4 ounces, Oakite Composition 
No. 2, 4 ounces, to' gallon water 200° F. Time 
required to clean this class of work 1 to 3 min- 
utes. Then rinse in hot water. Then wire or 
rack up the work, dip in O. P. C. solution (6 
ounces O. P. C. to gallon water) 200° P., rinse 
in cold water, then transfer to bright cyanide 



42 The Cleaning and Electro-Plating of Metals 



copper solution until coated all over with cop- 
per, then hang into an acid copper solution for 
from one to two hours, according to the class 
of work being done; then dip into bright dip 
composed of 1>^ parts oil of vitriol, 1 part 
nitric acid. Then rinse off thoroughly in clean 
water, and hang in brass solution until a nice 
yellow brass is obtained. About 2 or 3 minutes 
is sufificient. Then gold plate in salt water gold 
solution. 

Brass solution to be used at a temperature of 
80° F. in connection with salt water gilding 
solution. 

Water 1 Gallon. 

Sodium cyanide 96/98 7o 43^4 Ounces. 

Copper cyanide 70% 3 Ounces. 

Zinc cyanide 55% 1 Ounce. 

Soda ash 58% 2 Ounces. 

Ammonium chloride 1/3 Ounce. 

Prepare in order given. Brass anodes of 
80% copper and 20% zinc give best results in 
brass solution. 

The salt water gold solution should be made 
up of 

8 Ounces yellow ferrocyanide (yellow 
prussiate of potassium), 
24 Ounces carbonate of sodium, 
16 " phosphate of sodium, 
3 Pennyweights fulminate of gold, 
1 Gallon of water. 

In setting up this solution, use a red porous 
jar, and a copper kettle ; place the jar in the 
kettle and place a piece of sheet zinc around 



The Cleaning and Electro-Plating of Metals 43 



the porous jar. The sheet zinc should be about 
y2 inch thick. A copper rod should be attached 
to the zinc with rivets so as to get a good con- 



70 HAN6 WORK 
FROM 



SALT SOLUTION 

maclQ of rocf< 
^alt io register 



TEMP or 
so I or I ON 
i75 *> 




PORUS POT - 
ys Copper Rod 
Zinc 

^g THICK 

Topper pot 



57 CAM COIL 
or COPPER 
at bottom of 
copper pot. 



w^£frffj'^Mfr£f0ffffJ'/ff0^r*^fffr*sf^ffff^/f^/*/s 



Fig. 11— The Outfit for Salt Water Gilding. 



nection. Stand the porous jar and zinc on 
either wood or glass in the bottom of the cop- 
per kettle. The salt water which is used to 



44 The Cleaning and Electro- Plating of Metals 

form battery should be made from rock salt 
(which is very cheap), and a little sal-ammoniac, 
and should stand about 12° to 15° Be, and 
should be heated with a copper coil. 
Be sure and use copper or brass coil. 



SOME TALK ON LACQUER. 

First be sure the work to be lacquered has 
been thoroughly cleaned. A room free from 
dust should be fitted up with an oven heated 
to 140° F. and supplied wath a chimney or 
some means of carrying off the fumes of the 
lacquer, which are very disagreeable. 

For dip lacquering the lacquer is placed in 
an iron enameled vat. The articles perfectly 
clean are hung on hooks and dipped into the 
vat and held up for a few minutes to allow the 
superfluous liquid to run off. Then they are 
hung up to dr}^ in the oven. Dip lacquers are 
best thinned at night which will allow time to 
thoroughly blend. It is impossible to use a 
single solvent for an all around lacquer. Dip 
work requires one rate of evaporation, and 
spray work another rate. This is regulated by 
the solvents used and the proportions of each, 
and only experience can teach it. Brush lac- 
quer is the same as dip lacquer except that it 
should be used with a thicker body so it will 
spread well under the brush. A fitch or camel's 
hair brush should be used. 



The Cleaning and Electro-Plating of Metals 45 

The proper preparation of lacquer solvents 
calls for the highest degree of skill and care. 
The solvents must be prepared water white 
and free from water and acid. Lacquer will 
attract moisture from the air in a damp room, 
and thus cause considerable trouble. Lac- 
quered work which is thoroughly dried in an 




Fig. 12 — Rheostat and Wattmeter. 

Manufactured by Western Electric Company 

New York and Chicago 

oven will be softened up again if a lot of new- 
ly lacquered work is put in with it. 

For work that requires a heavy coat of high 
gloss lacquer, additions of various gums are 
made, some for hardness, some for gloss, and 
some for adhesion. Each in its proper pro- 
portion, and each with a certain amount of 
proper solvent to carry it. Some solvents pre- 
cipitate some gums, and their relative evapo- 
rating points are to be considered. Gum lac- 
quers unless a very heavy coat is required 
may be thinned out with three or four parts 
of thinner. If heavy coats are required they 
should be dried with considerable heat to 
harden them. A thoughtful, careful workman 



46 The Cleaning and Electro-Plating of Metals 

will obtain far better results with a fair grade 
of lacquer, than a careless workman will with 
the best grade. 

THE USE OF WATER DIP LACQUERS. 

This name is applied for the reason that 
after the article has been plated and without 
drying it can be dipped into the lacquer with- 
out in any way injuring the finish. These lac- 
quers are very beneficial for bright dipped 
finishes that are used in basket work. Also 
mat finish work on sheet brass, etc. Such 
work would tarnish at once if dried and then 
lacquered, and for this reason must be lac- 
quered as soon as the dipping method is over. 

For instance, sheet brass that is to be mat 
finished and dipped through bright dip often 
causes lots of trouble if one stops to dry it 
before lacquering. On the other hand if this 
work is dipped through a hot solution of Oakite 
Composition No. 1 and clean hot water, and 
then dipped into lacquer, there will be no 
trouble whatever. The dip lacquer for this class 
of work should be used very thin so it will run 
off without leaving a drip. I have lacquered 
thousands of pieces of this class of work in this 
way, and have had very good results. 

The water should he removed every day 
either by syphon, or by means of a faucet at 
the bottom of tank. A wire screen nickel 
plated with a coarse mesh should be placed a 
few inches from the bottom of lacquer tank. 



The Cleaning and Electro-Plating of Metals 47 

All dirt, etc., carried into the lacquer will sift 
through the screen, and can be drawn off 
with the water. 

THE USES OF AIR BRUSHES. 

The most up-to-date method of lacquering 
at the present time seems to be with the air 
brush called the ''Sprayer," which is operated 




Fi??. 15 — Sprayers and Air Filter. - 
Made by Eureka Pneumatic Spray Co., New York 

by compressed air, and everything from the 
largest to the smallest object can be lacquered 
or painted by means of this ''Sprayer." 

There are all styles of sprayers, some for 
lacquers and some for enamels, etc., and any 
number of colors can be blended together by 
use of the air brush. This method is far su- 
perior to the old way of using a camel's hair 
brush. The lacquer or enamels spread better 
and one can obtain a smoother surface. It 
also saves labor, as more work can be turned 
out in this way. Four or five pieces of work 



48 The Cleaning and Electro-Plating of Metals 



can be turned out with the spray while doing 
one with a brush, and at the same time give 
better resuks. It is a very good idea to use a 
hood, paint receiver and exhaust fan in con- 
nection with the ''Sprayer'' to remove the 
vapors which may arise. A pressure regulator 
and filter are also beneficial for fine work. 



:;' WATER 
BRASS COVER 



BEARINGS RING OILED 
AND BRONZE BUSHED 

FRICTION CLUTCH 




303-3 



Fig. 13 — Steel Ball Burnishing Barrel (single). 

The cut shows barrel in working position. 

Made by Baird Machine Company, Bridgeport, Conn. 



The Cleaning and Electro-Plating of Metals 



49 



BURNISHING WITH STEEL BALLS. 

This method of burnishing small metal arti- 
cles in tumbling barrels is a method of mixing 
articles such as buckles, chains, collar buttons, 
etc., with steel balls in the proper proportion 



j-i.^ 



WATER 



FRICTION CLUTCH PULLEYS 
^CLtyjCH LEVERS 




HARDWOOD LINING 
RASS COVER 



303-2 



Fig. 14 — Double Burnishing Barrel for Use with Steel Balls. 
Made by The Baird Machine Company, Bridgeport, Conn. 
The cut shows one Barrel horizontal and the other in position for 
dumping 

and rolling together in a thin solution of Oakite 
Composition No. 1, or Okeinco Soap, depend- 
ing on the work. The balls required must be 
hard and smooth. Small articles can be burn- 
ished and handled in large quantities in this 
way at a very small expense. 



50 The Cleaning and Electro-Plating of Metals 



I have bvirnished rose and green gold 
buckles in this way when I only wanted them 
to be burnished on the high lights and by 
tumbling them thirty minutes I got out very 
near the same class of work as I would had 
they been hand burnished, and the cost when 
the work is handled in this way is very small. 

Care should be taken not to allow the steel 
balls to become rustv- 



FORMULAS. 
Gun Metal Finish. 

On dip brass, copper, german silver, etc., or 
on any metal : 

Make a saturated solution of cyanide of 
sodium and arsenic, and use iron anodes and 
ordinary current. 

To make this solution, boil the. arsenic and 
cyanide together in about 2 gallons of water 
to 1>4 pounds of cyanide and 1 pound of arsenic, 
which will when dissolved, be about saturated. 
If not, add a little more arsenic. Do not in- 
hale the fumes as they are very poisonous. 
Acid Copper Solution: 

Water 1 Gallon. 

Sulphate of copper 32 Ounces. 

Sulphuric acid 2 '' 

Steel Color on Brass. 

Muriatic acid 1 Quart. 

Iron filings or chips 1 Handful. 

White arsenic . 1 Tablespoonful. 

Water 1 Gallon. 

Use hot. 



The Cleaning and Electro-Plating of Metals 51 

FORMULAS. 
Dark Brown Drab on Copper. 

Sulpho Cyanide of 

potash 2 Pennyweights, 

Nitrate of iron 5 '' 

Water 1 Gallon. 

Red Copper Solution: 

Water 75 Gallons. 

Prepared red copper 10 Pounds. 

Cyanide of sodium 10 '' 

Bisulphite of soda 10 " 

Brass Solution: 

Water 5 Gallons. 

Sodium cyanide 96/98% 14 Ounces, 

Copper cyanide 70% 7 Ounces. 

Zinc cyanide 3^ Ounces. 

Soda ash 4 Ounces. 

Bisulphite of soda 6 Ounces. 

Small amount of ammonia and arsenic. 

Cyanide Copper Solution: 

Carbonate of copper 5 Ounces. 

Bisulphite of soda 2 " 

Cyanide of potassium 10 " 

Water 1 Gallon. 

Royal Copper: 

Red lead 1 Pound. 

Banner lye 2 

Boil above 20 minutes in 1 gallon of water and 

add it to 10 gallons of water. Use copper anode. 

Rinse and heat until work becomes a cherry red, and 

develop color by buffing. Use a hard metal, copper 

preferred. 



52 The Cleaning and Electro-Plating of Metals 

FORMULAS. 
Tin Solution: 

Muriate of tin 6 Ounces. 

Phosphate of soda 6 " 

Acetic acid 2 " 

Water 1 Gallon. 

Use pure tin anode and low voltage. 
Acetic acid hardens deposit. 

Galvanizing Solution: 

Water 1 Gallon. 

Sulphate of zinc 2 Pounds. 

'' " aluminum 1^ Ounces. 

Zinc anodes. 

Strip for Brass, Copper or German Silver: 

Oil of vitriol 5 Gallons. 

Nitric acid 10 Ounces. 

Use hot and remove work as soon as stripped. 
When acid is saturated, dilute six times its volume 
with water, and precipitate with salt water. 

Gold Precipitate: 

After cutting gold with aqua regia, precipitate 
with aqua ammonia, (aqua regia is) 

Nitric acid 1 part. 

Muriatic acid 3 *' 

To Dissolve Arsenic: 

Arsenic can be dissolved in small quantities in 
the following alkalies and acids, readily if hot, 
and slowly if cold : 
Nitric acid Ammonia 

Sulphuric acid Cyanide of potassium 

Acetic acid Caustic potash 

Muriatic acid, Etc. Carbonate of soda. 

Banner Ive, etc. 



The.Cleaning and Electro-Plating of Metals 53 

FORMULAS. 

Hydrosulphuret of Potash: 

Caustic potash 8 Ounces. 

Pulverized sulphur 16 " 

Water 1 Quart. 

Boil one hour. After cooling, filter and use 
the clear liquid only. Add warm water, as it 
boils away. It will turn a deep red color. 

Quick Electrotype: 

Fine copper bronze 

powder 1 Ounce. 

Plumbago 1 

Rub above mixture on cast until a fine surface 
is presented, and plate in acid copper solution. 

Bright Pickle for Iron: 

Water 1 Gallon. 

Sulphuric acid 12 Ounces. 

Zinc 1 Ounce. 

Nitric acid 5' Ounces. 

Black Nickel Solution: 

Take (10) gallons of regular nickel solution 
(double sulphate of nickel and ammonia) standing 
6° Be, and add (1) pound sulphocyanide of potas- 
sium and half a pound (>4 lb.) C. P. sulphate of 
zinc. Use old anodes and a current of about ^ 
volts. Have the solution decidedly alkaline with 
ammonia. The zinc sulphate can be precipitated 
with sal-soda and washed thoroughly, then dissolved 
in strong ammonia. The latter method will make 
the solution sufiiciently alkaline. A small amount of 
aluminum sulphate added to this solution will im- 
prove it. 



54 The Cleaning and Electro- Plating of Mbtals 



FORMULAS. 

Gold Strip: 

Sulphuric acid C. P 1 Pound. 

Hydrochloric acid C. P 2-2/3 Ounces. 

Nitric acid 40° Be 1>4 Ounces. 

Keep free from water. 

Soldering Acid: 

Cut zinc with muriatic acid to saturation, and 
evaporate to 1/3 by boiling, and allow to cool, and 
then add an equal volume of saturated sal-ammoniac 
solution, and add about 10% crude glycerine. The 
boiling prevents sputtering when using. The 
glycerine prevents discoloration of work. 

Green Gold Solution: 

Water 1 Gallon. 

Gold as fulminate 4 Pennyweights. 

Nitrate of silver 1 Pennyweight. 

Cyanide 1 Ounce. 

Blue Oxidize on any Metal: 

Nitrate of lead 4 Ounces. 

Nitrate of iron 2 Ounces. 

Hyposulphite of soda 16 Ounces. 

Water 5 Gallons. 

Use hot. 

Blue Color on Steel: 

Heat steel to straw color and plunge into common 
machine oil. The work will take on a beautiful 
blue color. 

Flux for Melting Silver: 

Bicarbonate of soda 1 Pound. 

Cream of tartar 1^ " 

Silver 1 



The Cleaning and Electro- Plating of Metals 55 

FORMULAS. 
Dip Gold Solution: 

Water 1 Gallon. 

Yellow prussiate of pot- 
ash 12 Ounces. 

Phosphate of soda 10 Ounces. 

Sesquichloride of iron 2 Ounces. 

Fulminate of gold 5 Pennyweights. 

Solution must be kept in iron kettle and boiling 
when in use. 

Verde Green Solution: 

Water 3 Quarts. 

Chloride of calcium 4 Ounces. 

Chloride of ammonia 4 Ounces. 

Nitrate of copper 4 Ounces. 

Brush on work and stipple. 

Acid Dip for Mat Finish on Brass: 

Nitric acid 1 Part. 

Oil of vitriol 2 Parts. 

Add Sulphate of zinc to full saturation. If mat 

finish is too coarse, add more oil of vitriol; if too 

fine, add nitric. Use hot and keep water out of 

dip as much as possible. 

Olive Green on Brass: 

Acetate of copper 5 Ounces. 

Sulphate of copper 2 Ounces. 

Acetic Acid 2 Ounces. 

Water 1 Gallon. 

Use solution hot. 
1st. Brush work with a little pumice in 

water. 
2nd. Cold water rinse. 



56 The Cleaning and Electro- Plating of Metals 

FORMULAS. 

3rd. Place in coloring solution for 2 to 3 

minutes. 
4th. Cold water rinse. 
5th. Dry and lacquer. 

If not the shade desired, repeat. 

Electro Green Solution: 

Plate on any Metal. 
Sulphate of nickel 

(single nickel salts) 1>^ Pounds. 

Sulphate of copper ^ Pounds. 

Potassium bichromate 2 Ounces. 

Water 1 Gallon. 

Carbon or brass anodes. 
Use a current at 12 to 15 Volts. 
A very fine hard deposit of green is obtained. 
Electro Green for Relieving: 
Sulphate of nickel and ammonia 

(double nickel salts) 1^ Pounds. 

Sulphate of copper ^ Pounds. 

Potassium bichromate 2 Ounces. 

Water 1 Gallon. 

Carbon or brass Anodes. 
Use 12 to 15 volts pressure. 

Fine Brown Bronze on Copper: 

Nickel-ammonium sul- 
phate (Double nickel 

salts) 12 Ounces. 

Copper sulphate 2 Ounces. 

Water 2 Gallons. 

Use hot. Dip work in solution two or three minutes, 
take out, rinse in clean water, scratch brush with 
dry brush. If not the color desired, repeat as 
before. 



The Cleaning and Electro-Plating of Metals 57 

FORMULAS. 
Brown on Copper: 

Acetate of copper 5 Pounds. 

Nitrate of copper 5 Pounds. 

Salamoniac 1 Pound. 

Water 10 Gallons. 

Use hot. 
1st. Place in solution from 1 to 2 minutes. 
2nd. Cold water rinse. 
3rd. Scratch brush with a little pumice in 

water. 
4th. Place in solution again for 1 to 2 

minutes. 
5th. Cold water rinse. 
6th. Dry and lacquer. 

Light Brov/n on Copper: 

Water 1 Gallon. 

Sulphate of copper 1 Pound. 

Add caustic potash until solution turns black, 
then bring- back to dark green with sulphate of 
copper. Use solution hot. 

1st. Plate work in copper solution. 

2nd. Rinse in cold water. 

3rd. Place in coloring solution. 

4th. Cold water rinse. 

5th. Scratch brush with a little pumice in 
water. 

6th. Dip in O. P. C. solution. 

7th. Rinse in cold water. 

8th. Place in coloring solution until the de- 
sired shade is obtained. 

9th. Cold water rinse. * 

10th. Dry and lacquer. 



58 The Cleaning and Electro-Plating of Metals 

FORMULAS. 
Yellow Brown on Copper: 

Sulphate of copper 1 Pound. 

Chlorate of potassium 4 Ounces. 

Water 1 Gallon. 

Use solution hot. 
1st. Plate work in acid copper. 
2nd. Cold water rinse. 
3rd. Place in coloring solution for 2 

minutes. 
4th. Cold water rinse. 
5th. Scratch brush with a little pumice in 

water. 
6th. Dip in O. P. C. solution. 
7th. Cold water rinse. 
8th. Place in coloring solution imtil desired 

shade is obtained. 
9th. Cold water rinse. 
10th. Dry and lacquer. 

Barbadienne Bronze: 

First, plate object brass, then black nickel. 

Second, put on a mixture of sanguine and 
black lead, equal parts, and enough gum arable 
to make it stick, say about a wineglass full 
of gum arabic to a pint of water, and enough 
of water to make a very thin mixture. 

Third, take equal parts of sanguine and pale 
gold bronze, mix very fine by grinding. If 
that does not give the desired shade add more 
of either color and nothing else. Use good 
varnish relief as for anv bronze. 



The Cleaning and Electro-Plating of Metals 59 



FORMULAS. 
Flux to Clear Chloride of Silver of Chlorine: 

Add to chloride of silver in crucible before 
melting, 40% of calcined soda. Calcined soda 
is made by heating sal-soda on a hot surface 
until it is dry, and in a fine powdery form. 
To Crystallize Tin: 

Bring the tin article to a straw color by 
heating with blow pipe, and at once spray 
with cool water, and then plunge it into dilute 
sulphuric acid, which will bring out the 
crystals. 

A Simple Method for Testing Silver Solution 
for Silver: 

Take 4 ounces of silver solution to be tested, 
and precipitate with hydrochloric acid. If 
copper be present, it can be cut out easily with 
nitric acid. The nitric will not cut the silver. 
After the silver has gone to the bottom, draw 
oft' the fluid and place a small piece of zinc in 
the silver, which will with the acid or a few 
drops of sulphuric acid, drive out all chlorine 
and cyanogen, leaving it a dark colored pure 
silver which must be dried and weighed, which 
will give the true amount of silver per gallon 
of solution by multiplying by 32 the amount of 
silver found in 4 ounces of solution. As there 
are 128 ounces to a gallon, and we take 4 
ounces of solution, so we multiply by 32 which 
gives the number of ounces per gallon. 

Note: This method with proper manipulation 
will give pretty near perfect results. 



60 The Cleaning and Electro- Plating of Metals 



FORMULAS. 

To detect Iron in Sulphate of Copper: 

Dissolve sulphate of copper with ammonia 
to excess, which will redissolve the copper, 
and if iron be present it will remain at the 
bottom as hydrate of iron. 

Paint for Sectional Gold: 

. Take gumguac and break with a hammer 
until it is in powder form, and then dissolve in 
wood alcohol and let stand 24 hours. Then 
strain through cheese cloth, and add any- 
desired aniline color. Remove with lye or 
potash. 
Another very good stop-off is 

Collodion 1 Part. 

Lacquer 1 Part. 

Remove with lacquer thinner. 

Terra Cotta Bronze : 

Red sulphide of arsenic % Ounce. 

Pearl ash 6 Ounces. 

Water 1 Gallon. 

Sulphuret of potash 3 Pennyweights. 

Use boiling hot. 

Jet Black on Copper: 

Water 3 Gallons. 

Pulverized sulphur 9 Ounces. 

Caustic potash 1 Pound. 

Boil until sulphur is all dissolved, then filter and 
add to 20 gallons of water. Use cold on copper, 
and scratch brush work before immersion. Finish 
on soft rag wheel with kerosene and rouge. 



The Cleaning and Electro- Plating of Metals 61 

FORMULAS. 
Silver Solder: 

Sterling silver 40 Parts. 

Brass 30>^ " 

Bronze Solution: 

Water 1 Gallon. 

Cyanide of potassium 6 Ounces. 

Bisulphite of soda 2 Ounces. 

Carbonate of copper 4 Ounces. 

Chloride of tin Yi Ounce. 

Use bronze anodes. 

Black Nickel Solution: 

Water 1 Gallon. 

Nickel-ammonium sul- 
phate (Double nickel 
salts) 12 Ounces. 

Sulpho cyan potash , . . . . 3 Ounces. 

Carbonate of copper 2 Ounces. 

White arsenic 2 Ounces. 

Dip Silver Solution: 

Water 1 Gallon. 

Cyanide of potassium. . 2 Pounds. 

Caustic potash ^ Pound. 

Chloride of silver 1 Ounce. 

Stir well and use hot. 

Royal Copper Solution: 

Red lead >^ Pound. 

Caustic stick potash y^. Pound. 

Water 5 Gallons. 

Use pure lead anodes. 

Note : Copper plate work and then run in above 
solution for a couple of minutes, and then heat with 
blow-pipe flame and buff with red rouge. 



62 The Cleaning and Electro- Plating of Metals 



FORMULAS. 
Black Nickel Smut for French Grey: 

Oxide of nickel 5 Pounds. 

Carbonate of copper 1 Pound. 

Sal-soda 100 Pounds. 

Water 150 Gallons. 

Carbonate of ammonia 5 Pounds. 

Dissolve the copper and nickel in the ammonia. 

Verde Antique Paint. 

Chrome green, 
'' yellow, 
Zinc white, 
A very little yellow ocher. Mixed to desired 
consistency with turpentine. 
Dip Black on Brass: 

Water 1 Gallon. 

Carbonate of soda 4 Ounces. 

Carbonate of Copper 1 Pound. 

Ammonia 1 Quart. 

Use hot or cold. 
Crystallized Tin: 

Dip tin goods in a hot solution of water and 
sesquichloride of iron. 
To Separate Silver Metal from Copper: 

Cut the combination metals with nitric acid, 
and then precipitate with hydrochloric acid, 
which will throw the silver to the bottom as 
chloride, and hold the copper in the solution 
as chloride. 
To Recover Gold from an Old Solution: 

Place a quantity of scrap turnings or filings 
of zinc in the solution which will collect all 
the gold, after which draw ofif the solution, and 



The Cleaning and Electro- Plating of Metals 63 

FORMULAS. 

then cut the zinc with hydrochloric acid, leav- 
ing the gold at the bottom. 

Note : Cyanide of silver is not soluble in nitric 
acid unless heated. Cyanide of copper is soluble in 
nitric acid cold or hot. 

To remove fire stain from Sterling Silver: 

Nitric acid 1 Part. 

Water 1 " 

Use hot. 

To strip Silver from Steel: 

Water 1 Gallon. 

Cyanide of sodium 8 Ounces. 

Chloride of silver ^ Ounce. 

Use reverse current. 
Stop-Off or Paint for Etching: 

Virgin rubber dissolved with benzine. Add 
a small amount, say j4 ounce of asphaltum to 
a tablespoonful of virgin rubber. C^t the as- 
phaltum with turpentine, and add the rubber 
when dissolved to the asphaltum. This is 
strictly acid proof. 
Color Mixing Paints, Inks, etc. 
Red and black make brown, 
Lake and white make rose. 
White and brown make chestnut. 
White, blue and lake make purple, 
Blue and lead color make pearl, 
White and carmine make pink. 
Indigo and lamp black make silver gray, 
White and lamp black make lead color, 
Black and Venetian red make chocolate. 
Purple and whij;e make French white. 



64 The Cleaning and Electro-Plating of Metals 



FORMULAS 

Light green and black make dark green, 

White and green make pea green, 

White and emerald green make brilliant green. 

Red and yellow make orange. 

White, lake and vermillion make flesh color, 

Umber, white and Venetian make drab. 

White, yellow and Venetian red make cream, 

Blue, black and red make olive. 

Yellow, white and a little Venetian red make 

buff. 
White and green make bright green. 
White, blue and grey make pearl grey. 



ACID COPPER PLATING SOLUTION. 
Standard Formula: 

Water. . . 1 Gal. (U.S.) 

CrystalHzed copper sulphate 32 Ounces. 

Copper Determination: 

Put 5 CO. of the solution using a pipette, in- 
to a 250 c.c. beaker. Add about 100 c.c. water 
and 25 c.c. cone, sulphuric acid. Cut off a 
small strip (about 1>^ inches square) of alumi- 
num foil and place it in beaker. Heat gently 
and the copper will be precipitated out as met- 
allic copper. When solution becomes white, 
the copper can be filtered off using glass wool 
in funnel in place of filter paper. The filtrate 
is tested for copper by passing in HoS gas, 
which gives a black precipitate of copper sul- 
phide if it is present, indicating that it was not 



The Cleaning and Electro-Plating of Metals 65 

all precipitated by the aluminum foil. Wash 
the copper on the funnel once with hot water, 
then dissolve ofif the copper from the alum- 
inum foil with warm cone, nitric acid pouring 
into funnel and receiving the dissolved copper 
in an Erlenmeyer flask. When all the copper 
is dissolved, the solution is heated until all ni- 
trous fumes are gone, then add ammonium 
hydrate in slight excess and evaporate until 
most of the free ammonia has disappeared. 
Acetic acid is added in excess and heated. If 
solution is not clear it should not be heated 
too much as some of the copper will be lost by 
volatilization. When all the copper is in solu- 
tion cool and add ten grams potassium iodide, 
making sure that all of it is dissolved before 
beginning titration. The free iodine that is 
liberated in the reaction is titrated with stand- 
ard sodium thiosulphate solution, using starch 
as an indicator. The reaction between the 
copper acetate and potassium iodide is the 
formation of copper iodide and the liberation 
of iodine. 

When the potassium iodide is added a yel- 
low precipitate of cuprous iodide (Cuo I2) is 
thrown down. The starch is not added until 
towards the end of the titration. It produces 
a lilac color and the potassium thiosulphate 
solution is added slowly until one or two 
drops shows a change to a cream which re- 
mains permanent and is not changed, by the 
addition of more sodium thiosulphate solution. 



66 The Cleaning and Electro-Plating of Metals 

Calculation : 

Multiply the number of c.c. of sodium thio- 
sulphate used by the copper sulphate (Cu S 
O45 H20) value for 1 c.c, then divide by 5. 
The result is multiplied by 133.54 which gives 
ounces (av.) of copper sulphate per gallon 
(U. S.) 

The following example will illustrate it: 

Used 61.0 c.c. sodium thiosulphate solution, 
the copper sulphate value for 1 c.c. is .01964. 
This multiplied by 61 will equal 1.19804, then 
divided by 5 will equal .2396; multiply this by 
133.54 will equal 32 ounces of copper sulphate 
(Cu S O4) 5 H2O) per gallon. 
Standard sodium thiosulphate: 

Dissolve 39.2 grams of C. P. sodium thio- 
sulphate in water and dilute to two liters. 
This solution is quite stable. A slight decom- 
position might occur soon after making the 
solution due to carbon dioxide or oxygen in 
the water. The solution should be kept in a 
brown bottle as actinic light will decompose 
it. To standardize, take one gram of pure 
copper foil and dissolve in about 20 c.c. dilute 
nitric acid. When dissolved, dilute to 250 c.c. 
Then take out 50 c.c. with pipette (this is 
equivalent to .2 grams of copper) into an Er- 
lenmeyer flask. Boil out nitrous fumes ; then 
add ammonium hydrate in slight excess and 
evaporate until most of the free ammonia has 
disappeared. Acetic acid is added in excess 
and heated if solution is not clear. When all 
the copper is in solution, cool and add ten 
grams of potassium iodide. Then titrate with 



The Cleaning and Electro- Plating of Metals 67 

the sodium thiosulphate solution. The end 
point obtained when standardizing should be 
remembered and be the same when titrating 
samples. 

The number of c.c. of sodium thiosulphate 
used is divided into .2 grams, and the result 
will be the number of grams of copper per c.c, 
and this multiplied by 3.9283 will give the cop- 
per sulphate (Cu S O4 5 H2O) value of 1 c.c. 
of the solution. 

Starch Solution: 

Mix 0.25 gram of potato starch with 10 c.c. 
cold water; then add to boiling water with 
constant stirring to make about 400 c.c. When 
cold, use about 1 c.c. for titrating. It decom- 
poses very readily and should be prepared 
fresh every day. It produces an intense blue 
with iodine, and if brownish red indicates de- 
composition. The following are the reactions 
that occur: 

Copper acetate reacts with potassium iodide 
liberating free iodine as follows: 

2 Cu (C, H3 OO2 + 4K I = Cu. lo H- 4 
(KC2H3 02)+2I 

The free iodine colors the solution brown. 
The iodine reacts with the sodium thiosul- 
phate forming sodium iodide and sodium tet- 
rathionate. 

2 Na^ S2 O3 -f 2 I = 2 Na I -f Na^ S, O^. 
The blue compound that is formed when 
starch is mixed with iodine is of unknown 
composition. It behaves towards sodium thio- 



68 The Cleaning and Electro- Plating of Metals 

sulphate exactly as free iodine, and the reaction 
occurs as in the above equation. 

Sulphuric Acid determination: 

Measure out 5 c.c. of the solution with pip- 
ette into a 400 c.c. beaker; add 100 c.c. water 
and about 1 drop of a 5% solution of methyl 
orange. The solution will be a bright red. 
Place beaker on a white surface. From a 50 

N 
c.c. burette add — sodium hydrate until solu- 

1 
tion in beaker becomes a golden yellow. This 
indicates the end point. The number of c.c. 

N 
used of the — sodium hydrate is noted and cal- 

1 
culated as follows: 

N 
The number of c.c. — sodium hydrate used 
1 
is multiplied by the sulphuric acid value of 

N 
1 c.c. (exactly — Na O H will be .04904 

1 
grams) then divided by 5, and the result mul- 
tiplied by 133.54 will give ounces (av.) of sul- 
phuric acid (100% per gallon (U. S.). 
Example : 

N 
Used 8.0 c.c. — Na O H. The sulphuric 
1 



The Cleaning and Electro- Plating of Metals 69 



acid value of 1 c.c. is .04904. Multiply this by 
8 will give .39232 and divided by 5 will equal 
.07846; then multiply by 133.54 will give 10.48 
ounces (av.) of sulphuric acid per gallon 
(U. S.) 

N 
Standard — Sodium Hydrate : 

1 
Dissolve 80 grams C. P. sodium hydrate in 
water and dilute to two liters. Standardize 

N 
with — sulphuric acid, using methyl orange 

1 
as an indicator. 

N 
1 c. c. exactly -r- Na O H = .0400 grams 



1 



Na O H 



1 c. c. " " = .04904 grams 

H, S O,. 
The following reactions occur in titrating: 
H2 S O4 + 2 Na O H = Na^ S O4 + 2 H^ O 
Methyl orange is changed by alkalies to a yel- 
low and by acids to a pink red, therefore in 
titrating acidity it will indicate when sufficient 
sodium hydrate has been added, as an excess 
will change color to a yellow. 

Copper Determination: 

Put 10 c.c. of the solution with a pipette 
into a 250 c.c. beaker. Add 15 c.c. cone. H CI. 
Care should be taken not to inhale the gas, 
as it is very poisonous. Boil a few minutes 
then add 5 c.c. Ho Oo and continue boiling^ for 



70 The Cleaning and Electro-Plating of Metals 

fifteen minutes, adding water occasionally for 
the loss by evaporation. After decomposition 
of the cyanide 100 c.c. water are added and 
solution heated, then Ho S gas passed in for 
about ten minutes to precipitate the copper 
as Cu S. After precipitation, place beaker on 
water bath until precipitate collects and falls 
to the bottom, then filter it off washing with 
H2 S water three or four times. The filtrate 
is set aside for zinc determination. The filter 
paper containing the copper sulphide is re- 
moved from the funnel and the sulphide 
washed into a 250 c.c. beaker. The small por- 
tions that cannot be removed by washing can 
be dissolved by pouring on cone, nitric acid, 
adding sufilicient finally to dissolve all of the 
Cu S. Boil out excess of H N O3 and filter off 
any sulphur that has collected in small yellow 
lumps. Filter into an Erlenmeyer fiask and 
neutralize with N H4 O H, adding slight ex- 
cess; then boil until N H4 O H is faint. Add 
excess of acetic acid and boil for a couple of 
minutes until all the copper salts are in solu- 
tion. Cool to the ordinary temperature (to 
prevent volatilizing free iodine) and add 10 
grams of K I. The free iodine is titrated with 
standard sodium thiosulphate solution until 
the brown tinge has become faint, then add 
sufficient starch solution to produce a decided 
blue color. The titration is continued with 
vigorous shaking until a permanent cream 



The Cleaning and Electro- Plating of Metals 71 

color is produced. The starch solution should 
be weak as otherwise it tends to occlude 
iodine forming very small lumps that are not 
readily acted on by the thiosulphate solution. 
About .25 gram in 400 c.c. of water is the cor- 
rect strength to use. 



BRASS PLATING SOLUTION. 

Standard formula: 

Copper cyanide 70% 8^ Ounces. 

Zinc cyanide 55% 4^^ Ounces. 

Sodium cyanide 96/98% 16 Ounces. 

Water 1 Gallon. 

Calculation : 

Multiply the number of c.c. of sodium thio- 
sulphate used by the copper value for 1 c.c. 
Then divide by 10. The result multiplied by 
133.54 with equal ounces (av.) of copper per 
gallon. To convert this to copper carbonate, 
multiply by 1.8812. This will give copper car- 
bonate as figured from its theoretical formula 
(Cu C O3 Cu (OH)o Ho O). The formula dif- 
fers according to the method of manufactur- 
ing the copper carbonate. A true basic copper 
carbonate having the above formula would 
analyze as follows: 

Cupric oxide (Cu O) 66.54 

Carbon dioxide ( CO., ) 18.40 

Water (H,6) 15.06 

100.00 



12 The Cleaning and Electro- Plating of Metals 

Sodium Thiosulphate : 

Use the same solution as is used for acid 
copper. The copper carbonate (Cu C O3 Cu 
(OH)^ H,0. 

Value for 1 c.c. is found by multiplying the 
copper value by 1.8812 or to find any other 
value multiply bv the following factors : 

Cu X 1.2517 = Cu O 

Cu O X 0.7989 = Cu 

Cu X 1.8812 = Cu C O3 Cu (OH), H,0 

Zinc Determination: 

The filtrate from the Copper Sulphide is 
boiled to expel HoS, then neutralized with 
N H4 O H. Add 10 c.c. cone. H CI and 5 
grams of ammonium chloride and dilute to 
250 c.c. Heat solution nearly to boiling, then 
take out a portion, about 50 c.c. into another 
beaker; run into the remaining portion with 
vigorous stirring standard potassium ferro- 
cyanide solution until a brown tinge is pro- 
duced, when a few drops are taken out 
on a porcelain plate and mixed with a 
solution of uranium acetate. The portion that 
was taken into the beaker is then added in 
small portions at a time continuing the titra- 
tion after each portion is added. After the 
addition of the last portion the ferrocyanide 
solution is added by drops until the end point 
is obtained as a brown color with the uranium 
acetate. A correction for the reaction with 
the indicator, having the same conditions as 



The Cleaning and Electro- Plating of Metals 73 



above — that is, volume, temperature, ammon- 
ium chloride and free acid, but without the 
zinc — is determined. This correction, which 
will not amount to more than a few tenths of 
a c.c, is always subtracted from the burette 
reading when a titration is made. 
Calculation: 

Multiply the number of c.c. of potassium 
ferrocyanide solution used by the zinc value for 
1 c.c. then divide by 10. The result multi- 
plied by 133.54 will equal ounces of zinc per 
gallon. To convert this to zinc carbonate: 
(5 Zn O. 2 C O2 4 H_oO), 
multiply by 1.7345. 

Basic zinc carbonates differ in composition 
like the copper carbonate according to the 
method of manufacture. The true basic zinc 
carbonate has the above formula and would 
test as follows: 

Zinc oxide (ZNO) 71.77% 

Carbon dioxide (C O,) 15.52% 

Water (H O^) 12.71% 



100.00% 
Potassium Ferrocyanide : 

48.6675 grams of Merck's pure potassium 
ferrocyanide are dissolved in water and made 
up to 2250 c.c. and kept in a brown bottle. 

Uranium Acetate: 

Dissolve 4.4 grams of Merck's salt in 100 
c.c. of water and 2 c.c. of acetic acid. 



74 The Cleaning and Electro-Plating of Metals 

Standardizing the potassium ferrocyanide 
solution : 

0.3 grams of Merck's pure zinc are dissolved 
in 25 ex. of dilute H CI (1 part H CI, 3 parts 
HoO), then add 4 grams of pure N H4 CI and 
dilute to 250 c.c. with water and heat almost 
to the boiling point. Then run in about 58 c.c. 
of the potassium, ferrocyanide solution, stir- 
ring vigorous^. Take out two or three drops 
on a plate covered with parafifine and mix with 
a drop or two of the uranium acetate solution. 
Continue the titration until the first faint 
tinge of brown red color. Another portion 
of 0.3 grams of zinc is also titrated and should 
agree with the first portion within 0.1 c.c. A 
correction for the reaction, having the same 
volume of H2O, H CI, and same number of 
grams of N H4 CI but without the zinc, is 
determined. This correction is deducted from 
the number of c.c. used in titrating the 0.3 
grams sample. 

To find the value of 1 c.c. of potassium 
ferrocyanide solution in terms of zinc, divide 
0.3 by the corrected c.c. of the ferrocyanide 
used and the result will be the grams of zinc 
in 1 c.c. of the potassium ferrocyanide solu- 
tion. To find the value in terms of zinc ox- 
ide or carbonate, multiply the zinc value by 
the following factors: 

Zn X 1.2448 = ZnO 

Zn O X 0.8034 = Zn 

Zn X 1.7345 = 5 Zn O. 2 C Oo. 4 H.O 



The Cleaning and Electro-Plating of Metals 75 

The reactions that occur in titrating be- 
tween zinc chloride and potassium ferrocyanide 
vary according to temperature, quantity of 
sokition, and amount of acid. 

The probable reactions, using the above 
methods, are as follows : 
4 Zn Clo + 2 K4 Fe (C N)^ = 8 K CI + 2 

Zn, Fe C N« 
A secondary reaction then takes place: 
6 Zn. Fe (C N)e + 2 K, Fe (C N)« = 4 K. Zua 

(Fe (CN)/ ),. 



RESULTS OBTAINED BY ANALYSIS 
OF BRASS SOLUTION. 

In making up a brass solution, put in the 
metal at the rate of 5 parts carbonate of cop- 
per, and 3 parts carbonate of zinc. One would 
naturally think when a test was made of this 
solution that the same proportion of copper 
and zinc would be found, but I find that when 
an analysis is made the proportions are quite 
different, as there is always a sediment in the 
bottom of a brass solution, and this sediment 
in my experience is mostly zinc, with a very 
small amount of copper. So do not run away 
with the idea of being able to test your solu- 
tion and get the same amount as you weighed 
and put in, as it seems to be impossible to 
make a brass solution and take up all the 
metal. For instance try and make up a stand- 
ard brass solution, and that will show you 
that it is next to impossible to take up all the 



Id The Cleaning and Electro- Plating of Metals 

metal. I find the best way is to take a small 
amount of solution from the top of one of the 
tanks which is clear, and then standardize it 
by analysis, which will prove to you the true 
amount of metal in the solution. 

For example, make up a solution of 
12 Ounces copper carbonate, 
6 Ounces zinc carbonate, 
and then you say to yourself, I have a solution 
with the above named amounts in it. You are 
wrong, as a good part of the compound is ly- 
ing on the bottom of the tank, and is not 
in solution. 



CYANIDE COPPER PLATING 
SOLUTION. 
Copper Determination: 

Take 10 c.c. of the solution with a pipette 
into a 250 c.c. beaker. Add 15 c.c. cone. H CI. 
Care should be taken not to inhale the gas, 
as it is very poisonous. Boil a few minutes, 
then add 5 c.c. H0O2 and continue boiling for 
fifteen minutes, adding water occasionally for 
the loss by evaporation. After decomposition 
of the cyanide 100 c.c, of water is added 
and solution heated, then H2S gas passed in 
for about ten minutes to precipitate the copper 
as Cu S. After precipitation place beaker on 
water bath until precipitate collects and falls 
to the bottom, then filter it ofif washing with 
HoS water three or four times. The filter 



The Cleaning and Electro- Plating of Metals 11 

paper containing the copper sulphide is re- 
moved from the funnel and the sulphide washed 
into a 250 c.c. beaker. The small portions 
that cannot be removed by washing can be 
dissolved by pouring cone, nitric acid adding 
sufficient finally to dissolve all of the Cu S. 
Boil out excess of H N O3 and filter off any 
sulphur that has collected in small yellow 
lumps. Filter into an Erlenmeyer flask and 
neutralize with N H4 O H, adding slight excess ; 
then boil until N H^ O H is ' faint. Add 
excess of acetic acid and boil for a couple of 
minutes until all the copper salts are in so- 
lution. Cool to the ordinary temperature 
(to prevent volatilizing free iodine) and add 
10 grams of K I. The free iodine is titrated 
with standard sodium thiosulphate solution 
tmtil the brown tinge has become faint, then 
add sufficient starch solution to produce a 
decided blue color. The titration is continued 
with vigorous shaking until a permanent 
cream color is produced. The starch solution 
should be weak, as otherwise it tends to 
occlude iodine, forming very small lumps that 
are not readily acted on by the thiosulphate 
solution. About .25 gram in 400 c.c. of water 
is the correct strength to use. 

Calculation : 

Multiply the number of c.c. of sodium thio- 
sulphate used by the copper value for 1 c.c. 
Then divide by 10. The result multiplied by 
133.54 will equal ounces (av.) of copper per 



78 The Cleaning and Electro- Plating of Metals 

gallon. To convert this to copper carbonate 
multiply by 1.8812. This will give copper car- 
bonate as figured from its theoretical formula 
(Cu C O3 Cu (OH)o HoO). The formula dif- 
fers according to the method of manufacturing 
the copper carbonate. A true basic copper 
carbonate having the above formula would 
analyze as follows : 

Cupric oxide (Cu O) 66.54 

Carbon dioxide (C O.,) 18.40 

Water . (H,0) 15.06 

100.00 
Standard Solutions: 
Sodium Thiosulphate : 

Use the same_ solution as is used for acid 
copper. The copper carbonate (Cu C O3 Cu 
(O H)^ H2O 

Value for 1 c.c. is found by multiplying the 
copper value by 1.8812, or to find any other 
value multiply by the following factors: 

Cu X 1.2517 = Cu O 

Cu O X 0.7989 = Cu 

Cu X 1.8812 = Cu C O3 Cu (OH). H.O 



ASSAY TEST OF GOLD IN GOLD 
PLATING SOLUTIONS. 

Apparatus Necessary: 

Evaporating Dish, 
Crucible, 
Gas furnace, 
Cupel mould. 



The Cleaning and Electro- Plating of Metals 79 

Balance, 

100 c, c. Graduated flask. 

Chemicals : 

Sodium bicarbonate, 
Lead oxide, 
Argol, 
Bone ash. 

75 CO. of the solution is taken and evapo- 
rated to dryness in an evaporating dish. The 
residue is scraped off and put in a crucible 
(any good sand or clay crucible about 4>^ 
inches in height will do) with the following 
charge : 

20 grams Na H C O3 (Sodium bicarbonate) 

70 " Pb O (Lead oxide) 
3 " Argol (Cream of tartar) 

The whole is now thoroughly mixed in the 
crucible. It is now ready for the furnace. 
The heat is applied slowly at first, gradually 
increasing till the fiux melts. The flux has 
action and appears to boil mildly. The cruci- 
ble is left in the furnace about 25 minutes, 
being occasionally swirled and should not be 
removed until all action in the crucible has 
ceased. 

It is now taken out, swirled and allowed to 
cool. When cool the crucible is broken open 
and a lead button is found in the bottom. This 
button contains the gold and should be freed 
from any particles clinging to it by hammering. 

A bone ash cupel is now moulded and baked. 
Cupels are made of bone ash slightly moist- 
ened with water so that the powder will cling 



80 The Cleaning and Electro-Plating of Metals 

together. The mixture should be well kneaded 
before being put in the cupel mould. On com- 
ing out of the mould it is slowly baked in the 
furnace and if possible the cupel should be air 
dried for a week or so although this is not es- 
sential. 

The lead button is now put in the cupel and 
is ready for the furnace. A high heat is main- 
tained for a few minutes in order that the lead 
may melt quickly and oxidation commence as 
soon as possible. After the fumes of lead oxide 
are observed to rise from the surface of the 
cupel, the heat is moderated and as free a flow 
of air as possible is given. The lead is lost in 
the air as lead oxide, and a great deal is ab- 
sorbed by the cupel. When all the lead is gone 
the bead loses all lustre. The change of color 
is readily noticed and the cupel is withdrawn 
from the furnace with its small bead of gold. 

The gold is weighed and the pennyweights 
per gallon may be calculated as follows: 

Weight gold X 50.33 = number of grams per 
gallon. 

Grams per gallon of solution. 

Grams per gallon ^- 1.55 = penn3^weight per 
gallon. 



NICKEL PLATING SOLUTION: 

Standard Formula: 

Nickel ammonium sulphate (Dou- 
ble nickel salts) 12 Ounces. 

Water 1 Gallon. 



The Cleaning and Electro- Plating of Metals 81 

Nickel Determination : 

Measure out 25 c.c. of the solution with 
pipette into a 250 c.c. beaker. Add about 2 
c.c. Cone, sulphuric acid and heat almost to 
the boiling point. Pass in hydrogen sulphide 
gas to precipitate any metals such as copper, 
antimony, tin. If present, the precipitate is 
filtered off, washing with HoS water, and after 
w^ashing thoroughly the filtrate is boiled to 
expel HoS. When entirely free from H2S the 
iron is oxidized with 5 c.c. of hydrogen per- 
oxide and boiled until the h3^drogen peroxide 
is decomposed (takes about 15 to 20 minutes). 

The iron found in nickel salts is an impurity 
and should be present only as a trace. After 
boiling about twenty minutes the iron is pre- 
cipitated with ammonium hydrate filtered and 
washed once or twice with hot water. The 
precipitate is dissolved in dilute sulphuric acid 
(1 part sulphuric acid and three parts water) ; 
it is then reprecipitated with ammonium hy- 
drate; the second filtrate is then added to the 
first. This second precipitation is necessary 
with large amounts of iron, as the iron 
occludes some of the nickel when it is precipi- 
tated. 

The filtrate is transferred to a 500 c.c. 
beaker, boiled to expel free ammonia and neu- 
tralized with sulphuric acid, using litmus 
paper as an indicator. When solution is neu- 
tral add 2 c.c. Cone, ammonium hydrate and 
dilute solution to 250 c.c. with water; then 



82 The Cleaning and Electro- Plating of Metals 



cool to 68^ F. It is now ready to be titrated 
with standard potassium cyanide solution as 
follows: Run into the solution from a 50 c.c. 
burette 5 c.c. of standard silver nitrate solu- 
tion (prepared according to directions under 
standard solutions). Add 0.5 c.c. of a 2% 
solution of potassium iodide which throws 
down a precipitate of silver iodide. This pre- 
cipitate is used as an indicator to show when 
all of the nickel has combined with the potas- 
sium cyanide solution as an excess of potassium 
cyanide will dissolve it. The beaker containing 
the solution is placed on a black surface and 
standard potassium cyanide solution is run in 
slowly from a 50 c.c. burette until the disappear- 
ance of the precipitate of silver iodide. This 
indicates the end point, but usually an excess 
of potassiuni cyanide is used to dissolve the 
silver iodide, then this excess can be found by 
running in the silver nitrate until the first 
appearance of a precipitate; then one or two 
drops of the potassium cyanide solution should 
give a very clear solution. The number of c.c. 
of silver nitrate and potassium cyanide used is 
read ofT and amount of nickel ammonium 
sulphate calculated as follows: 

The c.c. of silver nitrate used is converted 
into equivalent c.c. of potassium cyanide by a 
factor found under silver nitrate solution. 
After multiplying by this factor the c.c. ob- 
tained are subtracted from c.c. of potassium 
cyanide used, and the result will be the cor- 



The Cleaning and Electro-Plating of Metals 83 

rect number of c.c. of potassium cyanide used 
for titrating sample. The nickel ammonium 
sulphate value of 1 c.c. of the potassium 
cyanide solution (see potassium cyanide solu- 
tion for this value) is multiplied by the c.c. 
of potassium cyanide used, and divided by 25 
c.c, then the result multiplied by 133.54 will 
give the ounces (av.) of nickel ammonium sul- 
phate. 

(Ni S O4 (N HJ. S O^-f 6H0O) per gallon 
(U.S.) 

The following example will illustrate it : 

The factor to convert c.c. of silver nitrate 
to equivalent c.c. of potassium cyanide was 
found to be 0.2. Used 30.4 c.c. of silver 
nitrate, and multiplying by 0.2 will equal 6.08 
c.c. potassium cyanide. Run into the solution 
74.88 c.c. of potassium cyanide, then subtract- 
ing 6.08 will leave 68.8 c.c. of potassium 
cyanide actually used. 

The value of 1 c.c. of potassium cyanide 
solution in grams of nickel-ammonium sul- 
phate was found to be .03265, which multiplied 
by 68.8 c.c. will give 2.24632, and divided by 
25 c.c. will equal .0898, then multiplied by 
133.54 will give 12 ounces of nickel-ammonium 
sulphate per gallon. 

Standard Silver Nitrate Solution: 

Dissolve 11.6 grams of C. P. silver nitrate in 
water and dilute to two liters. This solution 
is to be kept in a brown bottle, as the light 
will decompose it. To find the factor to give 



84 The Cleaning and Electro- Plating of Metals 

equivalent c.c. of potassium cyanide solution, 
take 15 c.c. of the silver nitrate, add 2 c.c. 
Cone, ammonia and dilute with water to 250 
c.c. Add 0.5 c.c. of potassium iodide and run 
in potassium cyanide solution slowly until dis- 
appearance of precipitate. The number of 
c.c. used is divided by 15 c.c, and the result 
will be the factor to convert c.c. of silver nitrate 
to c.c. of potassium cyanide. 

Standard Potassium Cyanide Solution : 

Dissolve 44.5 grams of C. P. potassium 
cyanide (Merck's Reagent) in water and dilute 
to two liters. Solution should be kept in a 
brown bottle and will have to be standardized 
every few days as it does not remain stable. 

Standardize as follows: Weigh 1 gram C. 
P. nickel (Electrolytic) and dissolve in 5 c.c. 
of dilute nitric acid and 10 c.c. of dilute sul- 
phuric acid and a little water. When dissolved, 
transfer to a 250 c.c. graduated flask ; cool, and 
dilute to 250 c.c. with water. Take out 50 c.c. 
with pipette which is equivalent to .2 grams of 

1 1 

nickel. (50 c.c. is — of 250 c.c. and — of 1 oram 

5 5 

is .2 gram). Neutralize with ammonia; then 
add 2 c.c. in excess, and titrate with the silver 
nitrate and potassium cyanide, as in the 
directions already given. The c.c. of potassium 
cyanide used is divided into .2 grams, and the 
result multiplied by 6.7314 will be the nickel- 
timmonium sulphate (Ni S O4 (N Hi)- S O4 



The Cleaning and Electro- Plating of Metals 85 

6Ho O) value for 1 c.c. of the potassium cyanide 
solution. 

The following are the reactions that occur: 

Silver nitrate reacts with potassium iodide 
as follows: 

Ag N O3+K l=Ag I+K N O, 

The reaction of nickel sulphate with potas- 
sium cvanide is as follows: 

Ni S O4+4K C N=(K C N)o Ni (C N),) + 
K,S O,. 

The silver iodide is dissolved by the potas- 
sium cyanide during titration forming the 
double salt potassium silver cyanide as in the 
following equation : 

Ag If 2K CN = KCNAgC N+K I. 

If cobalt is present it will be estimated with 
the nickel. Its presence is shown by the solu- 
tion darkening. 



&.' 



SILVER PLATING SOLUTION. 
Standard Formula: 

Silver Chloride 4 Ounces (av.) 

Potassium Cyanide 12 " (av.) 

Water 1 Gallon (U.S.) 

Silver Determination: 

Measure out 25 c.c. of the solution with a 
25 c.c. pipette into a 400 c.c. beaker, using a 
long rubber tube on pipette for aspirating the 
solution so as to prevent it being sucked into 
the mouth. Add 100 c.c. of water to the beaker 
and heat almost to the boiling point, then pre- 
cipitate the silver as silver sulphide (Ag2 S) 
with hydrogen sulphide gas (H2 S). When 



86 The Cleaning and Electro-Plating of Metals 

complete precipitation has taken place, filter 
off the silver sulphide on an E. and A. filter 
paper 13 cm., washing the precipitate with 
hydrogen sulphide water several times. The 
paper and precipitate is removed from the 
funnel, and the silver sulphide washed from 
the paper into a 250 c.c. beaker with water. 
(The adhering pieces on the paper can be re- 
moved with cone, nitric acid). The silver sul- 
phide is dissolved in a small quantity of cone, 
nitric acid, then the solution is boiled to expel 
the nitrous fumes, as their presence will inter- 
fere with the titration. After boiling off the 
nitrous fumes the solution is cooled and 
diluted to about 150 c.c. with water and 
titrated as follows : 

Add 5 c.c. of a cold saturated solution of 
iron alum (ferric ammonium sulphate). If 
the solution becomes turbid, nitric acid is 
added drop by drop until clear. Place the 
beaker on a white surface and add the stand- 

N 
ard — potassium sulphocyanate solution from 

10 
a 50 c.c. burette with constant stirring until a 
faint permanent reddish tinge of ferric sul- 
phocyanate — Fe2 (S C N)6 — is produced. 
The number of c.c. used is noted and the 
ounces of silver chloride per gallon calculated 
as follows : 

N 

Multiply the c.c. of — potassium sulpho- 

10 



The Cleaning and Electro- Plating of Metals 87 

cyanate used by the silver chloride value for 1 

' N 
c.c. (for exactly — it is .01433 grams), then di- 

10 
vide by 25 (number of c.c. taken for analysis). 
This will give the grams of silver chloride in 
1 c.c. of the plating solution. To convert this 
to ounces (av.) per gallon (U. S.), multiply 
by 133.54. 

The following example will illustrate it: 
N 
Used 52.3 c.c. — potassium sulphocyanate ; 

10 
multiply by .01433 will equal .74946, and 
divide by 25 will equal .02997 grams silver 
chloride in 1 c.c. of plating solution, then mul- 
tiply by 133.54, and the result will be 4 ounces 
of silver chloride per gallon (U. S.) 

N 
Standard — Potassium Sulphocyanate: 
10 

Dissolve 20 grams of potassium sulphocyan- 
ate in water and dilute to two liters. Stand- 
ardize it by taking 0.4 grams granulated silver 
(999 fine) in a 250 c.c. dilute nitric acid (equal 
parts of cone, nitric acid and water). After 
the silver is dissolved, the solution is boiled to 
expel nitrous fumes. When entirely free from 
nitrous fumes (this is shown by no more yel- 
low fumes coming off) the solution is cooled 
and diluted to 150 c.c. with water; then add 
5 c.c. of indicator (iron alum) and titrate with 



S8 The Cleaning and Electro- Plating of Metals 

the potassium sulphocyanate solution until 
the first permanent pink is produced. The 
number of c.c. used divided into 0.4 gram, 
will give the grams of silver in 1 c.c. of the 
solution, and this multiplied by 1.3287 will give 
the grams of silver chloride in 1 c.c. of the 
potassium sulphocyanate solution. 

The following are the reactions that take 
place in titrating: 

Ag N O3 + K S C N=Ag S C N + K N O3 

An excess of potassium sulphocyanate then 
reacts with iron alum as follows : 

2 Fe N H4 (S 04)0 + 6 K S C N^Fe.. (S C 
N)e N HJ, S 0,+3 K, S O,. 

This method is accurate in the presence of 
copper (not exceeding 70%), arsenic, antimony, 
cadmium, lead, bismuth, tin, zinc, iron and 
manganese. Mercury if present will interfere, 
and therefore should be removed before 
titrating. 

Uncombined Cyanide determination: 

Take 10 c.c. of the plating solution into a 
400 c.c. beaker; add about 100 c.c. water and 
2 c.c. of Cone, ammonium hydrate and about 
1 c.c. of 2% potassium iodide solution; then 

N 
run in from a 50 c.c. burette — silver nitrate 

10 
until a permanent white precipitate of silver 
iodide is formed. This indicates the end point. 
The number of c.c. of silver nitrate used is 



The Cleanin^g and Electro-Plating of Metals 89 

noted and calculated as follows : 
N 

1 ex. — Ag N O3=.005202 gms. C. N. The 
10 
number of c.c. Ag- N O3 used times .005202 — 
''x" grams C N in 10 c.c. of the plating solu- 
tion. Then '*x" grams C N divided by 10 will 
give the grams of C N in 1 c.c. of plating solu- 
tion, which multiplied by 133.54 will be the 
ounces (av.) of C N per gallon (U. S.). 

This determination is figured as C N, not as 
K C N, as the majority of the potassium cya- 
nides on the market contain large quantities 
of Na C N which would be included when 
figuring the uncombined C3^anide as K C N. 

The uncombined cyanide is the K C N or 
Na C N that has not combined with the Ag 
CI to form the double salt Ag C N K C N as 
in the equation : 

Ag Cf+2K C N-=Ag C N K C N+K CI. 

In titrating the free K C N or Na C N with 
Ag N O3 the double salt (Ag C N K C N) is 
not titrated by the Ag N O3, only the free K 
C N or Na C N as in the following equations : 

Ag N O3+2 K C N=Ag C N K C N+K N O. 

Then an excess of Ag N O3 reacts with the 
Kl as follows: 

Ag N O.+K I=Ag I+K N O3 
N 
Standard — Silver Nitrate Solution: 
10 

Dissolve 33.978 grams of pure silver nitrate 
in water and dilute to two liters. To stand- 



90 The Cleaning and Electro-Plating of Metals 

ardize take 0.25 grams C. P. sodium chloride 
(Merck's Reagent) in a 400 c.c. beaker; add 
100 c.c. water, and when all of the salt has 
been dissolved add 1 c.c. of a 2% solution of 
neutral potassium chromate as an indicator. 

Place beaker on a white surface and titrate 
with the silver solution from a burette until 
a faint red tinge is obtained. The end point 
is somewhat difficult to distinguish. The faint 
red tinge can be more distinctly seen if an- 
other beaker containing 150 c.c. water and 1 
c.c. of the chromate solution is compared with 
it. The sodium chloride solution should be 
neutral or faintly alkaline and cold. The 
number of c.c. of silver nitrate solution used 

N 
(exactly --r would take 42.76 c.c.) divided into 

0.25 grams sodium chloride will give the num- 
ber of grams of sodium chloride in 1 c.c. of the 
silver nitrate solution. The other values can 
be found by multiplying the sodium chloride 
value by the following factors : 
Na CI X 0.8898 = CN 
" 2.2275 = KCN 
- 1.6767 = NaCN 

N 
1 c.c. Exactly — AgNO, = .005202 gms. CN 

1 c.c. " -^AgN03=- .01302 " KCN 

1 c.c. " ^AgN03 = . 009802 " NaCN 

1 c.c. " -^ AgN03 = . 005846 " NaCl 



The Cleaning and Electro- Plating of Metals 91 

CYANIDE DETERMINATION IN 
POTASSIUM CYANIDE. 

Weigh off about 15 grams of the potassium 
cyanide in a tared weighing bottle, dissolve in 
water without heat and dilute to 500 c.c. 

Take out 10 c.c. with pipette into a beaker, 
add 2 c.c. of Cone. N H4 O H and 1 c.c. K I 
solution (2%) and about 100 c.c. water, then 

N 
run in — Ag N O3 from a burette until a per- 

10 
manent white precipitate of silver iodide is 
formed. The number of c.c. of Ag N O3 used 
multiplied by .005202 and divided by the 
weight taken, then multiplied by 100 = % CN 
in sample. 
Example : 

15.281 grams of potassium cyanide were dis- 
solved and diluted to 500 c.c, then 10 c.c. 

N ' 
(.3051 grams) required 23.45 c.c. — Ag N O3 

10 
23.45 X .005202=.121988-^.3051=.3999X100 
= 39.99% C N. 
Factors : 

CN X 1.8843 = NaCN 
CNX 2.5033 = KCN 
NaCN X 0.53071 =CN 
KCN X 0.39947 = CN 
AgX 1.3287 ==AgCl 
Ag X 0.4822 -= CN 
AgCl X 0.36291 = CN 
AgX 0.90847 = KCN 
Ag X 0.68382 = NaCN 



92 The Cleaning and Electro- Plating of Metals 




The Cleaning and Electro- Plating of Metals 93 

TOTAL POTASSIUM AND SODIUM 

CYANIDE DETERMINATION 

IN SILVER SOLUTION. 

In an apparatus as shown in Fig. 10 distill 10 
c.c. of silver solution to be tested for cyanide, 
potassium cyanide, or sodium cyanide, as fol- 
lows : 

Take 10 c.c. of silver solution, add 10 c.c. of 
water (HoO), and place in Jena Kjeldahl Flask 
(C) connected with stop cock funnel (D) and 
connect with glass tube into Liebig Condenser 
(F). On receiving end of condenser have bot- 
tles (K & M) connected to collect steam. 
Place in funnel (D) 25 c.c. sulphuric acid 
(Ho S O4) and 25 c.c. water (Ho O) and then 
place in bottle (K) at receiving end of con- 
denser 50 c.c. water (Ho O) and 1 gram of 
sodium hydrate (Na O H). Add the sulphuric 
acid and water that is in funnel (D) to, the sil- 
ver solution in Kjeldahl Flask (C) drop by 
drop while over flame (B). A slow stream of 
water must be kept running through the con- 
denser (F) by connecting the lower rubber 
tube (J) with a water cock (O). When the 
solution is boiled in the Kjeldahl Flask (C) by 
means of a Bunsen burner flame (B) placed 
under flask, the steam passes into the inner 
tube of the condenser (F). As this is sur- 
rounded by cold water the steam condenses 
and the distilled cyanide solution collects in 
the receiver (K) at the other end of con- 
denser. When all the cvanide has come over. 



94 The Cleaning and Electro-Plating of Metals 

you will notice acid fumes in the flask. Then 
titrate the cyanide solution which has been 

N 
collected in the receiver with — silver nitrate 

10 
solution (Ag N O3). 

Before titrating, take cyanide solution col- 
lected from condenser, and add 1 c.c. potas- 
sium iodide solution (K I) 2% solution, and 
about 100 c.c. water, then run in from a bur- 

N 
ette — silver nitrate until a permanent white 

10 
precipitate of silver iodide is formed. This in- 
dicates the end point. The number of c.c. of 
silver nitrate used is noted and calculated as 
follows : 
N 

1 c.c. — Ag N O3 = .005202 gms. C N. The 
10 
number of c.c. Ag N O3 used times .005202 = 
''x" grams C N in 10 c.c. of the plating solu- 
tion. Then "x" grams C N divided by 10 will 
give the grams of C N in 1 c.c. of plating solu- 
tion, which multiplied by 3785 will be the 
grams cyanide per gallon. As there are 30 
grams in one ounce, divide by 30 which will 
be ounces per gallon. As there is only about 
39 to 40% cyanide in potassium cyanide, you 
multiply the amount of cyanide by 2.5, which 
will give you the amount of potassium cyanide 
per gallon in silver solution, minus 20% which 
is lost. 



The Cleaning and Electro-Plating of Metals 95 

The 20% loss in the above method is due 
to the C3^anide decomposing, etc., and about 
7% of it turns into carbonate of potassium. 



POTASSIUM CARBONATE IN SILVER 
SOLUTION. 

In an apparatus as shown in Fig. 1(> distill 
5 c.c. of silver solution to be tested for potas- 
sium carbonate as follows : 

Take 5 c.c. of silver solution, add 5 c.c. water, 
and place in Jena Kjeldahl flask connected 
with stop cock funnel, and connect with glass 
tube into Liebig Condenser. On receiving 
end of condenser have bottle connected to col- 
lect steam. Place in funnel 25 c.c. sulphuric 
acid (Ho S O4) and 25 c.c. water (Ho O) and 
then place in bottle at receiving end of con- 
denser 50 c.c. saturated solution of barium 
hydroxide and water. This is water, that has 
taken into solution all the barium hydroxide 
that it will hold. 

Add the sulphuric acid and water that is in 
funnel to silver solution drop by drop while 
over flame. A slow stream of water must be 
kept running through the condenser by con- 
necting the lower rubber tube with a water 
cock. When the solution is boiled in the 
Kjeldahl flask by means of a bunsen burner 
flame placed under flask, the steam passes 
into the inner tube of the condenser. As 
this is surrounded by cold water the steam 
condenses and the potassium carbonate in the 



96 The Cleaning and Electro- Plating of Metals 

solution is broken up and carbon dioxide 
(C O2) is distilled over. The carbon dioxide 
combines with the barium hydroxide to form 
barium carbonate and water after the follow- 
ing equation : 

C 0,+Ba (O H),=Ba C O3+H, O. 

The barium carbonate is a white precipitate. 

When all is distilled over acid fumes will be 
seen in the flask, and the flame is taken away. 

The barium carbonate is filtered off and 
heated in a weighed crucible. 

When heated the barium carbonate is 
changed to barium oxide and is then weighed 
as such. 

Ba C Oa^Ba O+C O,. 

The barium oxide is figured to potassium 
carbonate in oz. per gal. as follows: 

Wt. Ba O multiplied by .9=Wt. K, C O,. 
Wt. Ko C O3 -^ No. of c.c. taken. Then mul- 
tiplied by 133.54 = no. ozs. of K2 C O3 in 1 
srallon of silver solution. 



The Cleaning and Electro- Plating of Metals 97 



CHEMICALS USED IN PLATING ROOM. 



Sulphuric Acid, 
Nitric Acid, 
Muriatic Acid, 
Citric Acid, 
Boracic Acid, 
Arsenious Acid, 
Hydrofluoric Acid^ 
Bichromate of Potassium 
Caustic Potash or Potas- 
sium Hydrate, 
Cyanide of Potassium, 
" Silver, 
" " Copper, 
" " Zinc, 
Sodium Carbonate, 
Bicarbonate, 
Bisulphite, 
" Hyposulphite, 

Nitrate, 
'' Phosphate, 
Chloride, or 
Common Salt, 
Sodium Cyanide, 
Barium Sulphide, 
Ammonium " 
Hydrosulphuret Am- 
monium, 
Ammonium Chloride, 
Hydrate, 
Yellow Prussiate of Pot- 
ash, or 
Potassium Ferrocyanide, 
Sodium " 

Barium '' 



Acetic Acid, 

Ammonia, 

Caustic Soda or Sodium 

Hydrate, 
Potassium Sulphuret, 
Copper Chloride, 
*' Carbonate, 
'^ Sulphate, 
Acetate, 
Nitrate, 
Zinc Carbonate, 

'' Sulphate, 

'' Chloride, 
Nickel Carbonate, 

" Sulphate, 

" Chloride, 

" Ammonium Sul- 
phate, 
Iron Sulphate, 

'' Chloride, 
Sesquichloride of Iron, 
Nitrate of Tin, 
Tin Chloride, or Muriate 

of Tin, 
Gold Chloride, 
Silver 

Platinum " 
Silver Nitrate, 
Lead " 

" Acetate, 
Lye or Potash, 
Kalye, 
Calcium Chloride. 



98 The Cleaning and Electro- Plating of Metals 

APPARATUS AND CHEMICALS NECES- 
SARY FOR THE METHODS OF 
ANALYSIS OF THE SOLUTIONS. 

y2 pound Potassium Iodide, C.P.cryst.U.S.P. 

3/2 pound Potassium Sulphocyanate, C. P. 

1 ounce Phenolphtaleine, Pure, 

3/2 pound Acid Carbolic, C.P. 

2 ounces .... Silver Nitrate, C.P. 

1 pound Sodium Hydroxide Electrolytic 

sticks, 

1 ounce Nickel Metal Co. free Gran. C.P. 

25 g-rams Copper Electrolytic Foil Kb. Reag. 

3^ pound Aluminum Metal Foil 5/1000 in.,. 

pure, 

1 pound Hydrogen Peroxide Marchand, 

y2 pound Ammonium Molybdate C.P. 

5 pounds . . . .Iron Sulphide Broken Plates, 

1 book 100 Strips each Litmus Blue, 

1 book 100 Strips each Litmus Red, 

4 pounds . . . .Ammonium Hydrate 26 deg. 

Baker's anal, chem, 
9 pounds . . . .Acid Sulphuric, 1, 

6 pounds . . . .Acid Hydrochloric, 

7 pounds . . . .Acid Nitric, 

1 Bunsen Burner, 

4 feet Rubber Tubing, Black, 1^5 inch 

diam. (4ozs.j 

3 feet Rubber Tubing, 34 ^^^ch diam. (6 

ozs.) 

1 Tripod, Iron, 

3 Beakers, Jena, Griffin's, 250 c.c, 

2 ditto 400 c.c, 

2 ditto 600 c.c, 

2 Flasks, Jena Erlenmeyer 500 c.c, 



The Cleaning and Electro- Plating of Metals 99 

1 Cylinder, Lipped, Graduated 100 

c.c. 

2 Burettes, Mohr's, 50 c.c. jV c-c 

subdivisions, 

1 .ditto 100 c.c. 1^0 c.c. 

subdivisions, 

1 Support for Burettes, 

1 Flask, 250 c.c. 

1 " 1000 c.c. 

Reagent Bottles White Labels and 
Black Letters : 

1 Reagent Bottle 12 oz. ''Acid Sul- 
phuric Cone." 

1 Reagent Bottle 12 oz. "Acid Sul- 
phuric Dil." 

1 Reagent Bottle 12 oz. "Acid Hy- 
drochloric." 

1 Reagent Bottle 12 oz. ''Acid Ni- 
tric." 

1 Reagent Bottle 12 oz. ''Ammonium 

Hydrate." 

2 Funnels, Glass, 3 inch diameter, 

1 Nest of three Funnels, Glass, 

6 Funnels Cylindrical, 2 ozs., 

1 Pipette 5 c.c. 

1 " 10 c.c. 

1 " 25 c.c. 

1 Pipette 50 c.c. 

1 " 100 c.c. 

1 Thermometer 400 deg. F., 

1 box Labels, No. 201, 

1 box " 223, 

1 Spatula, Blade 3 inches, 

1 Gas Generator, Dudley's for H2S 

1 pound Glass Tubing, ^ inch external di- 
ameter, 



100 The Cleaning and Electro- Plating of Metals 



pound Glass stirring- rods, assorted sizes, 

File, Triangular, 4 inch, 

Wash Bottle, 1 Pint, 

Wash Bottle, 1 Quart, 

Support for Funnels, 

2 pkgs Filter Papers, E. & A. diameter 13 

cm., 

3 Watch Glasses 3^ inch diameter, 

3 " " 4 inch diameter. 

^ dozen Test tubes 6 x ^ inch., 

1 Support for 13 Test Tubes, 

1 Kjeldahl Connecting Bulbs Tube, 

small, 

1 Condenser, Liebig end drawn out 

15 inches, 

2 Drying Tubes (Peligot Tubes) 6 

inch., 

3 Rubber Stoppers, solid. 

No. 1, 6 ozs. 

3 Rubber Stoppers, solid, 

No. 3, 6 ozs. 

3 Rubber Stoppers, solid. 

No. 6, 6 ozs. 



The Cleaning and Electro-Plating of Metals 101 

ANTIDOTES FOR POISONS USED IN 
PLATING ROOM. 

Nitric, hydrochloric or sulphuric acids : Ad- 
minister abundance of tepid water to act as 
an emetic, or swallow milk, the white of eggs, 
some lime, or a mixture of chalk and water. 

If those acids in a concentrated state have 
been spilled on the hands or any part of the 
skin, apply a mixture of whiting and olive oil. 
If the quantity is very small, simple swilling 
with plenty of cold water will suffice. 

Useful Mixture: 

Mixture, if in cases of burning with strong 
sulphuric acid, is formed with 1 ounce of quick 
lime slacked with 54 of an ounce of water, then 
adding to a quart of water. After standing 2 
hours, pour off the clear liquid and mix it with 
olive oil to form thin paste. 

Potassium Cyanide, Hydrocyanide Acid, etc.: 

If cyanides, such as a drop of an ordinary 
plating solution, has been accidentally swal- 
lowed, water as cold as possible should be run 
on the head and spine of the sufferer, and a 
dilute solution of iron acetate, citrate, or tar- 
trate administered. 

If hydrocyanic acid vapors have been in- 
haled, cold water should be applied as above, 
and the patient be caused to inhale atmospheric 
air containing a little of chlorine gas. 

It is a dangerous practice to dip the arms 
into a plating solution to recover any work 



102 The Cleaning and Electro-Plating of Metals 

that has fallen off the wires, because the skin 
often absorbs cyanide liquids, causing painful 
sores, in such a case, wash well with water and 
apply with olive oil and lime water. 

Mixture, Alkalies: 

These bodies are the opposite to acids in 
character, so that acids may be used as anti- 
dotes. It is preferable to employ weak acids, 
such as vinegar or lemonade ; but if these are 
not at hand, then use exceedingly dilute sul- 
phuric or even nitric acid diluted, so that it 
just possesses a decidedly sour taste. After 
about 10 minutes take a few teaspoonfuls of 
olive oil. 

Mercury Salts: 

The white of an Qgg is the best antidote 
in this case. 

Sulphur or sulphureted hydrogen are also 
serviceable for the purpose. 

Copper Salts: 

The stomach should be quickly emptied by 
means of emetic, or in want of this, the patient 
should thrust his finger to the back of his 
throat so as to tickle the uvala, and thus in- 
duce vomiting. After vomiting, drink milk, 
white of an egg, or gum water. 

Lead Salts: 

Proceed as in case of copper salts. Lemon- 
ade, soda water and sodium carbonate are 
also serviceable. 



The Cleaning and Electro- Plating of Metals 103 

Acid Vapors: 

Admit immediately an abundance of fresh 
air, and inhale the vapors of ammonia, or a 
few drops of ammonia may be put into a glass 
of water and the solution drank. Take plenty 
of hot drinks, and excite warmth by friction. 
Employ hot foot-baths to remove the flood 
from the lungs. Keep the throat moist by 
sipping milk. 

Removal of Stains, etc.: 

To remove stains of copper sulphate, or salts 
of mercury, gold, silver, etc., from the hands, 
wash them with a very dilute solution of 
ammonia, and with plenty of water ; if the stains 
are old ones, they should be rubbed with the 
strongest acetic acid, and then treated as above. 

GREASE, OIL, TAR, ETC., may be easily 
removed from the hands or clothes by washing 
with a little Oakite or rubbing with a rag 
saturated with a solution of Oakite of 1 ounce 
per gallon. 



104 The Cleaning and Electro- Plating of Metals 



WEIGHTS AND MEASURES. 



Linear Measurements. 

10 millimeters (mm.) = 1 centimeter (cm.) 
10 centimeters = 1 decimeter (dm.) 

10 decimeters = 1 meter (m.) 

Equivalent, 1 inch = 2.5 cm. (approximately) 

Square Measurements. 

100 sq. millimeters (mm") = 1 sq. centimeter (cm') 
100 sq. centimeters = 1 sq. decimeter (dm") 
100 sq. decimeters = 1 sq. meter (m^) 

Cubic Measurements. 

1000 cu. millimeters (mm") = 1 cu. centimeter 

(cc or cm') 
1000 cu. centimeters = 1 cu. decimeter (dm') 
1000 cu. decimeters =1 cu. meter (m') 
Equivalents, 1000 cc. = 1 liter (1 1.) 

1 1. = 1 quart (approximately) 



Conversion Table. 

1 cc. of water (S.T.P.) = 1 g. 
1 1. of water (S.T.P.)=1 k. 
30 g. = 1 ounce (approximately) 
1 k, = 2.2 pounds (approximately) 
1 g. = 15 gr. (approximately) 
1 1. hydrogen = .09 g. (approximately) 



The Cleaning and Electro- Plating of Metals 105 



Troy Weight. 
24 grains = 1 dwt. 

20 dwts. = 1 ounce. 

12 ounces = 1 pound. 

Used for weighing gold, silver and jewels. 



Apothecaries' Weight. 



20 grains 



= 1 scruple. 
3 scruples = 1 dram. 

8 drams = 1 ounce. 

12 ounces == 1 pound. 

The ounce and pound in this are the same as in 
Troy weight. 

Avoirdupois Weight. 



27 11-32 grains 
16 drams 
16 ounces 
25 pounds 
4 quarters 
2,000 pounds 
2,240 pounds 

2 pints 

8 quarts 

4 pecks 

36 bushels 



== 1 dram. 

= 1 ounce. 

= 1 pound. 

^ 1 quarter. 

= 1 cwt. 

= 1 short ton. 

= 1 long ton. 

Dry Measure. 

= 1 quart. 

= 1 peck. 

= 1 bushel. 

= 1 chaldron. 



Liquid Measure. 

4 gills = 1 pint. 

2 pints = 1 quart. 

31j^ gallons = 1 barrel. 

2 barrels = 1 hogshead. 



106 The Cleaning and Electro- Plating of Metals 

Time Measure. 

60 seconds = 1 minute. 

60 minutes = 1 hour. 

24 hours = 1 day. 

7 days = 1 week, 

28, 29, 30 or 31 days = 1 calendar month (30 ds.) 
365 days = 1 year. 

Circular Measure. 

60 seconds = 1 minute. 



60 minutes 


= 1 degree. 


30 degrees 


= 1 sign. 


90 degrees 


= 1 quadrant. 


4 quadrants 


= 12 signs. 


360 degrees 


1 circle. 




Long Measure. 


12 inches 


= 1 foot. 


3 feet 


= 1 yard. 


5y2 yards 


= 1 rod. 


40 rods 


= 1 furlong. 


8 furlongs 


= 1 statute mile 


3 miles 


= 1 league. 



Weight Table. 

10 milligrams (mg.) = 1 centigram (eg.) 
10 centigrams == 1 decigram (dg.) 

10 decigrams = 1 gram (g.) 

1000 grams = 1 kilogram (k.) 



The Cleaning and Electro- Plating of Metals 107 



Square Measure. 



144 sq. inches 

9 sq. feet 

30^4 sq. yards 

40 sq. rods 

4 roods 

640 acres 



1 sq. foot. 
1 sq. yard. 
1 sq. rod. 
1 rood. 
1 acre. 
1 sq. mile. 



Cubic Measure. 



1,728 cubic inches 
27 cubic feet 
128 cubic feet 
40 cubic feet 
2,150.42 cubic inches = 1 standard bushel. 
268.8 cubic inches = 1 standard gallon. 
1 cubic foot = about four-fifths of a bushel. 



1 cubic foot. 

1 cubic yard. 

1 cord (wood). 

1 ton (shpg.) 



Approximate Metric Equivalents. 



1 decimeter 


= 


4 


inches. 


1 meter 


= 


1.1 


yards. 


1 kilometer 


= 


Vs 


of mile. 


1 hektar 


= 


2/2 


acres. 


1 stere or cu. meter 


= 


'A 


of a cord 


1 liter 


= 


1.06 


qt. liquid. 


1 liter 


= 


0.9 


qt. dry. 


1 hektoliter 


= 


2^ 


bush. 


1 kilogram 


== 


2 1/5 


lbs. 


1 metric ton 


== 


2,200 lbs. 



108 The Cleaning and Electro- Plating of Metals 



Measure of Volume. 



1 cu. centimeter 


= 


0.061 


cu. in. 


1 cu. decimeter 


= 


0.0353 


cu. ft. 


1 cu. meter 


= 


1.308 


cu. yd. 


1 stere 


= 


0.2759 cd. 


1 liter 


= 


0.908 


qt. dry. 


1 liter 


= 


1.0567 


qt. liq. 


1 dekaliter 


= 


2.6417 


gal. 


1 dekaliter 


= 


.135 


pks. 


1 hektoliter 


= 


2.8375 


bush. 


1 cu. inch 


= 


16.39 


cu. cent'rs 


1 cu. foot 


= 


28.317 


cu. deci'rs 


1 cu. yard 


= 


0.7646 


cu. M'r. 


1 cord 


= 


3.624 


steres. 


1 quart dry 


= 


1.101 


liters. 


1 quart liquid 


= 


0.9463 


liter. 


1 gallon 


= 


0.3785 


dekaliter. 


1 peck 


= 


0.881 


dekaliter. 


1 bushel 


= 


0.3524 hektoliter. 



The Cleaning and Electro- Plating of Metals 109 



METRIC EQUIVALENTS. 
Linear Measure. 



1 centimeter 


= 0.3937 


inches. 


1 decimeter 


= 3.937 


in.=0.328 ft. 


1 meter 


= 39.37 


in.= 1.0936 yds. 


1 dekameter 


= 1.9884 


rods. 


1 kilometer 


= 0.62137 mile. 


1 inch • 


= 2.54 


centimeters. 


1 foot 


= 3.048 


decimeters. 


1 yard 


= 0.9144 


meter. 


1 rod 


= 0.5029 


dekameter. 


1 mile 


= 1.6093 


kilometers. 




Square Measure 




1 sq. centimeter 


= 0.1550 


sq. inches. 


1 sq. decimeter 


= 0.1076 


sq. feet. 


1 sq. meter 


= 1.196 


sq. yards. 


1 ar 


= 3.954 


sq. rd. 


1 hektar 


= 2.47 


acres. 


1 sq. kilometer 


= 0.386 


sq. m. 


1 sq. inch 


= 6.452 


sq. centimeters 


1 sq. foot 


= 9.2903 


sq. decimeters. 


1 sq. yard 


= 0.8361 


sq. meter 


1 sq. rod 


= 0.8361 


sq. ar. 


1 acre 


= 0.4047 


hektar. 


1 sq. mile 


= 2.59 
Weights. 


sq. kilometers. 


1 gram 


= 0.03527 


ounce. 


1 kilogram 


= 2.2046 


lbs. 


1 metric ton 


= 1.1023 


English ton. 


1 ounce 


= 28.85 


grams. 


1 pound 


= 0.4536 


kilogram. 


1 English ton 


= 0.9072 


metric ton. 



110 The Cleaning and Electro-Plating of Metals 



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1 12 The Cleaning and Electro-Plating of Metals 



CYLINDRICAL VESSELS, TANKS, 
CISTERNS, ETC. 

For Ordinary Requirements Use O. P. C. V2 Lb. Per Gallon 

Diameter in Feet and Inches, Area in Square Feet and 
U. S. Gallons Capacity for One Foot in Depth. 



DIAMETER 


Area 


Gallons 


diameter 


Area 


Gallons 






Square 


One Foot 






Square 


One Foot 


Feet 


Inches 


Feet 


Depth 


Feet 


Inches 


Feet 


Depth 


1 




.785 


5.87 


4 


6 


15.90 


118.97 




1 " ' 


.922 


6.89 


4 


7 


16.50 


123.42 




2 


1.069 


8.00 


4 


8 


17.10 


127.95 




3 


1.227 


9.18 


4 


9 


17.72 


132.56 




4 


1.396 


10.44 


4 


10 


18.35 


137.25 




5 


1.576 


11.79 


4 


11 


18.99 


142.02 




6 


1.767 


13.22 












7 


1.969 


14.73 


5 


..... 


19.63 


146.88 




8 


2.182 


16.32 


5 




20.29 


151.82 




9 


2.405 


17.99 


5 


2 


20.97 


156.83 




10 


2.640 


19.75 


5 


3 


21.65 


161.93 




11 


2.885 


21.58 


5 


4 


22.34 


167.12 










5 


5 


23.04 


172.38 


2 


..... 


3.142 


23.50 


5 


6 


23.76 


177.72 


2 




3.409 


25.50 


5 


7 


24.48 


183.15 


2 


9 


3.687 


27.58 


5 


8 


25.22 


188.66 


2 


3 


3.976 


29.74 


5 


9 


25.97 


194.25 


2 


4 


4.276 


31.99 


5 


10 


26.73 


199.92 


2 


5 


4.587 


34.31 


5 


11 


27.49 


205,67 


2 


6 


4.909 


36.72 










2 


7 


5.241 


39.21 










2 


8 


5.585 


41.78 


6 


..... 


28.27 


211.51 


2 


9 


5.940 


44.43 


6 




30.68 


229.50 


2 


10 


6.305 


47.16 


6 


6 


33.18 


248.23 


2 


11 


6.681 


49.98 


6 


9 


35.78 


267.69 




..... 


7.069 


52.88 


7 




•38.48 


287.88 






7.467 


55.86 


7 


"3"' 


41.28 


308.81 




2 


7.876 


58.92 


7 


6 


44.18 


330.48 




3 


8.296 


62.06 


7 


9 


47.17 


352.88 




4 


8.727 


65.28 












5 


9.168 


68.58 


8 


..... 


50.27 


376.01 




6 


9.621 


71.97 


8 




53.46 


399.88 




7 


10.085 


75.44 


8 


6 


56.75 


424.48 




8 


10.559 


78.99 


8 


9 


60.13 


449.82 




9 


11.045 


82.62 












10 


11.541 


86.33 


9 




63.62 


475.89 




11 


12.048 


90.13 


9 


■3" 


67.20 


502.70 










9 


6 


70.88 


530.24 




..... 


12.566 


94.00 


9 


9 


74.66 


558.51 






13.095 


97.96 












2 


13.635 


102.00 


10 




78.54 


587.52 




3 


14.186 


106.12 


10 


■3" 


82.52 


617.26 




4 


14.748 


110.32 


10 


6 


86.59 


647.74 




5 


15.321 


114.61 


10 


9 


90.76 


678.95 












1 cubic foot 




Igall 


on equals 2Z\ c 


ubic inches, 


equals 


equa 


s 0.13368 



cubic feet. 



7.4805 



The Clean'ing and Electro- Plating of Metals 113 



CONTENTS 



ILLUSTRATIONS. 

Page 

Ammeter for Electro-Plating Work 19 

Automatic Moving Plating Tank 29 

Electro-Plating Dynamo — General Electric Company. . IS 

Motor Generator Set — General Electric Company 21 

Plan of Apparatus for Analysis of Plating Solutions. . . 92 
Plan View of Modern Plating and Polishing Room. ... 17 

Rheostat Used in Plating Room 25 

Rheostat and Wattmeter — Weston Electric Company . . 45 

Salt W ater Gilding Outfit 43 

Sprayers and Air Filters 49 

Steel Ball Burnishing Barrel — Single — Baird Machine 

Company 47 

Steel Ball Burnishing Barrel — Double — Baird Machine 

Company 48 

U. S. Junior Plating Barrel — U. S. Electro-Galvanizing 

Company 30-31 

Voltmeter Used in Electro-Plating — Weston Electric 

Company 22 

ARTICLES. 

Air Brushes, Use of 49 

Aluminum, Plating on 28 

Aluminum, To Copper Plate 23 

Aluminum, To Nickel Plate 22 

Antidotes for Poisons 101 

Apparatus and Chemicals for the Analysis of Solutions 98 

Arsenic, To Test 52 

Articles, Cleaning, Before Galvanizing 11 

Articles, Stopping-Off 12 

Articles, To Strip 13 

Black Nickel Smut for French Grey 62 

Brass, Copper or German Silver, Cleaning of 9 

Brass Plating Solution 24 

Burnishing with Steel Balls 47 

Capacities of Cylindrical Vessels 112 

Capacities of Rectangular Tanks 1 10 

Cast Iron Stove Work, Cleaning of 8 



1 14 The Cleaning and Electro- Plating of Metals 



Page 

Chemicals Used in Plating Room 97 

Cleaning Agents, Other 6 

Copper Plating 23 

Copper Plating and Cleaning in Same Solution 24 

Cyanide in Potassium Cyanide, Determination of 90 

Cyanide, Potassium and Sodium. Determination in Silver 

Solution 93 

Cyanide, To Eliminate 11 

Die Casting Metal, Cleaning of, for Plating 10 

Electrical Requirements, Basis of 1 

Electric Cleaner on Lead and Antimony 9 

Finish, Bright for Silver 41 

Finish, Dark Brow^n Drab on Copper 51 

Finish, Dark Brown or Copper on Brass 41 

Finishes, Gun Metal 50 

Finish, Matt Dip on Brass 55 

Finish, Old Ivory 37 

Finish, Ormolu Gold on Lead Work 41 

Finish, Rose Gold 38 

Finish, Royal Copper 51 

Finish, Steel on Brass 50 

Formula for Barbadienne Bronze 58 

Formula for Blue Color on Steel 54 

Formula for Bright Pickle for Iron 53 

Formula for Cold Strip 54 

Formula for Crystallized Tin 59 

Formulas for Mixing Paints and Inks 63 

Formula for Potassium Hydro-sulphuret. 53 

Formula for Quick Electrotyping 53 

Formula for Silver Solder 61 

Formula for Soldering Acid 54 

Flux for Melting Silver 54 

Flux to Clear Chloride of Silver 59 

Gilders' Wax 40 

Gilding Inside of Articles 39 

Gold, Sectional Paint for 60 

Gold Plating on Jevv^elry 40 

Gold, To Recover from Old Solution 62 

Iron, To Detect, in Sulphate of Copper 60 

Jewelry, Cleaning of 10 

Lacquer or Enamel, To Remove 12 

Lacquers, Some Talk on 44 

Lacquers, Use of Water Dip 46 

Lead and Antimonial Articles, Cleaning of 8 



The Cleaning and Electro- Plating of Metals 115 



Page 

Metric Equivalents 108 

Methods of Analysis 64 

Acid Copper Solution 64 

Brass Solution 71 

Cyanide Copper Solution 76 

Nickel Solution 80 

Silver Solution 85 

Nickel Plating 19 

Paint, Stop-otT, for Etching 63 

Paint, Verde Antique 62 

Plating Room, Electrical Requirements Necessary in. . 16 

Potassium Carbonate in Silver Solution 95 

Silver Plating Casket Hardware 32 

Silver Plating Holloware 34 

Silver Plating Lead or Spelter 36 

Silver Plating Steel Knives 33 

Silver Solution, Method of Testing 59 

Silver, To Remove Fire from 63 

Silver, To Separate from Copper 62 

Silver, To Strip from Steel 63 

Silver White or Argent Ivory 36 

Solution, Acid Copper 50 

Solution, Black Nickel 61 

Solution, Blue Oxidize on Any Metal 54 

Solution, Brass 51 

Solution, Bronze ; 61 

Solution, Brown on Copper 57 

Solution, Cyanide Copper 51 

Solution, Dip Black, on Brass 62 

Solution, Dip Silver 61 

Solution, Electro Green 56 

Solution, Electro Green for Relieving 56 

Solution, Fine Brown on Copper 56 

Solution for Black Nickel 53 

Solution for Gold Dip , 55 

Solution, Galvanizing 52 

Solution, Gold Precipitate 52 

Solution, Green Gold 54 

Solution, Jet Black on Copper 60 

Solution, Light Brown on Copper 57 

Solution, Olive Green on Brass 55 

Solution, Red Copper 51 

Solution, Royal Copper 61 

Solution, Salt Water Gold 42 



1 16 The Cleanikg and Electro-Plating of Metals 



Page 

Solution, Silver Bright 35 

Solution, Strip, for Brass, Copper or German Silver. . , 52 

Solution, Terra Cotta Bronze 60 

Solution, Tin 52 

Solution, Verde Green * 55 

Tables of Weights and Measures 104 

Tin, Crystallized, Method for 62 

Tin, Preparing, for Nickel Plating 9 

Tumbling Barrel Plating 30 

White and Red Lead, To Remove 12 

Work, Cleaning of 3 

Zinc Plating 26 



237 90 










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